Composition for ferroelectric thin film formation, method for forming ferroelectric thin film, and ferroelectric thin film formed by the method thereof

ABSTRACT

Disclosed is a composition for ferroelectric thin film formation which is used in the formation of a ferroelectric thin film of one material selected from the group consisting of PLZT, PZT, and PT. The composition for ferroelectric thin film formation is a liquid composition for the formation of a thin film of a mixed composite metal oxide formed of a mixture of a composite metal oxide (A) represented by general formula (1): (Pb x La y )(Zr z Ti (1−z) )O 3  [wherein 0.9&lt;x&lt;1.3, 0≦y≦0.1, and 0≦z≦0.9 are satisfied] with a composite oxide (B) or a carboxylic acid (B) represented by general formula (2): C n H 2n+1 COOH [wherein 3≦n≦7 is satisfied]. The composite oxide (B) contains one or at least two elements selected from the group consisting of P (phosphorus), Si, Ce, and Bi and one or at least two elements selected from the group consisting of Sn, Sm, Nd, and Y (yttrium).

TECHNICAL FIELD

The present invention relates to a composition for the formation of aferroelectric thin film, a method for forming a ferroelectric thin film,and a ferroelectric thin film formed by the method thereof.

This application is a divisional application of U.S. application Ser.No. 12/736,944, filed Nov. 24, 2010, and claims the benefit of JapanesePatent Application No. 2009-105883 filed on Apr. 24, 2009, JapanesePatent Application No. 2009-085819 filed on Mar. 31, 2009, JapanesePatent Application No. 2009-105076 filed on Apr. 23, 2009, JapanesePatent Application No. 2009-060348 filed on Mar. 13, 2009, JapanesePatent Application No. 2009-105885 filed on Apr. 24, 2009, JapanesePatent Application No. 2009-102817 filed on Apr. 21, 2009, JapanesePatent Application No. 2009-085830 filed on Mar. 31, 2009, JapanesePatent Application No. 2009-102815 filed on Apr. 21, 2009, and JapanesePatent Application No. 2009-059019 filed on Mar. 12, 2009, thedisclosures of which are incorporated herein in their entireties byreference.

BACKGROUND ART

As a method for preparing a ferroelectric film, there is generally knowna method in which an alkoxide or organic acid salt of individualconstituent metals is dissolved in a polar solvent to prepare a mixedsolution, and the resulting solution is applied and dried on a metalsubstrate to form a coated film, followed by baking at a temperatureequal to or higher than its crystallization temperature, thereby forminga dielectric thin film (for example, see Patent Document 1).

Further, for the purpose of use in DRAMs or nonvolatile memories, thereis known a method of producing a dielectric device which includesforming an amorphous or crystalline dielectric film on a semiconductorsubstrate, and doping impurities on the dielectric film by a thermaldiffusion method, an ion implantation method, an ion doping method, orthe like (for example, see Patent Document 2). The Patent Document 2discloses a PZT film as a metal dielectric film, and P (phosphorus) ionsas impurities. Doping of P (phosphorus) can improve memory retentioncharacteristics of DRAMs or nonvolatile memories equipped with adielectric capacitor.

Further, for the purpose of use in a capacitor of semiconductor memorycells, it has been disclosed a method of forming a ferroelectric film inwhich, upon forming a ferroelectric film of PZT by a sol-gel method, alead-titanium double alkoxide or lead-zirconium double alkoxide isformed, the reaction product is subjected to hydrolysis and acondensation reaction to make a high-molecular weight version, a rawmaterial solution is prepared, the raw material solution is applied, theapplied raw material solution is dried to form a dried film, and thedried film is baked (for example, see Patent Document 3). The PatentDocument 3 describes that, in order to suppress fatigue (decrease inresidual polarization value) or leakage current due to the inversion ofapplied voltage upon the use of the formed PZT thin film, the fourthmetal element such as lanthanum, niobium, or iron may be added to theraw material solution. According to Patent Document 3, hydrolysis andcondensation reactions of individual double alkoxides uniformly proceed,and PZT thin films formed from this sol-gel solution exhibitsatisfactory electrical characteristics such as smooth surface, largeamount of residual polarization and small amount of leakage current, soit is possible to meet the required performance.

Further, for the purpose of use in a variety of devices taking advantageof electrical or optical properties, there is known a composition whichis used in the formation of a PLZT ferroelectric thin film, wherein thecomposition is a liquid composition for the formation of a thin film ofa mixed composite metal oxide of a composite metal compound Arepresented by PLZT and a composite metal oxide formed of one or moreelements selected from Bi, Si, Pb, Ge, Sn, Al, Ga, In, Mg, Ca, Sr, Ba,V, Nb, Ta, Sc, Y, Ti, Zr, Hf, Cr, Mn, Fe, Co, Ni, Zn, Cd, Li, Na and K,the composition including a solution wherein a compound constituting themetal oxide is dissolved in an organic solvent in such a proportion asto provide the desired metal atom ratio (for example, see PatentDocument 4). In the Patent Document 4, the use of such a compositionenables the crystallization even at a low temperature of 450° C. orlower, upon the formation of a ferroelectric thin film.

In addition, for the purpose of use in nonvolatile memories, there is adisclosure of a mixed liquid for the formation of a ferroelectric thinfilm, wherein Ca, Sr, or La is added to PZT (for example, see PatentDocument 5).

Further, when a voltage is applied to a thin film of PZT which is arepresentative ferroelectric substance, the leakage current densityincreases which is confirmed to consequently result in a dielectricbreakdown.

To cope with this problem, an attempt has been made to improve leakagecharacteristics by the addition of trace elements to a ferroelectricthin film such as PZT film, but the results are still unsatisfactory(for example, see Patent Document 6 and 7).

In addition, an attempt has been made to decrease the leakage currentdensity by increasing the thickness of the ferroelectric filmconfiguration, but such an attempt has the problem of lowering thecapacitance.

As countermeasures against the above-mentioned problems, it has beendemonstrated that a specific permittivity of a non-doped PZT film can beimproved from 400 to 700 by the doping of cerium nitrate at 1 at. % on aPZT film having a film thickness of about 1 μm, but such a specificpermittivity is still low, thus being insufficient for practical use(for example, see Non-Patent Document 1).

Further, when a ferroelectric film is configured into a thin film, asufficient specific permittivity cannot be obtained due to the action ofgreat stress resulting from the restraint of a substrate (for example,see Non-Patent Document 2).

For these reasons, it has been attempted to improve the specificpermittivity through the addition of trace elements (for example, seeNon-Patent Document 1).

Further, film thickness reduction theoretically leads to an increase incapacitance, so it has been attempted to improve the capacitance throughthe reduction of the film thickness.

Further, it has been attempted to improve the dielectric strengthvoltage characteristics by doping PZT with Bi (for example, see PatentDocument 6). However, the Patent Document 6 merely exemplifies Bi as adoping element, but there is no working example illustrating thepractical application of doping. In addition, there is no measurement ofthe specific permittivity therein.

Further, it has been described that the addition of acetic acid to a PZTsol-gel liquid improves the stability of a solution in air (for example,see Patent Document 8). There has been described that upon the additionof an organic acid ester to a PZT sol-gel liquid, a PZT film withimproved (111) orientation can be obtained taking advantage of latticeinformation of the underlying Pt(111) film (for example, see PatentDocument 9).

However, there is no report showing an improvement in specificpermittivity of the PZT film when organic acid is added to a PZT sol-gelliquid.

Patent Document

-   [Patent Document 1] Japanese Unexamined Patent Application, First    Publication No. S 60-236404 (page 3, right bottom column, line 11 to    page 4, left bottom column, line 10, page 5, right top column, line    10 to the same page, left bottom column, line 17)-   [Patent Document 2] Japanese Unexamined Patent Application, First    Publication No. H 5-343641 (claims 3, 4, and 8, paragraph numbers    [0001], and [0065])-   [Patent Document 3] Japanese Unexamined Patent Application, First    Publication No. H 7-252664 (claims 2, 3, 7, and 8, paragraph numbers    [0001], [0035], [0117], and [0118])-   [Patent Document 4] Japanese Unexamined Patent Application, First    Publication No. 2003-2647 (claim 1, paragraph numbers [0001] and    [0013])-   [Patent Document 5] U.S. Pat. No. 6,203,608 (FIELD OF THE INVENTION,    claim 1)-   [Patent Document 6] Japanese Unexamined Patent Application, First    Publication No. H 8-153854 (claim 1, and claim 3)-   [Patent Document 7] Japanese Unexamined Patent Application, First    Publication No. 2005-217219 (claim 5)-   [Patent Document 8] Japanese Unexamined Patent Application, First    Publication No. H 11-220185 (claim 7, paragraph number [0008])-   [Patent Document 9] Japanese Unexamined Patent Application, First    Publication No. 2004-277200 (claim 10)

Non-Patent Document

-   [Non-Patent Document 1] S. B. Majumder, D. C. Agrawal, Y. N.    Mohopatra, and R. S. Katiyar, “Effect of Cerium Doping on the    Microstructure and Electrical Properties of Sol-Gel Derived    Pb_(1.05)(Zr_(0.53−d)Ce_(d)Ti_(0.47))O₃(d=10at %) Thin Films”,    Materials Science and Engineering, B98, 2003, pp. 25-32 (FIG. 2)-   [Non-Patent Document 2] Ceramics, 42, 175-180 (2007) (p. 175, left    column, lines 20 to 22)

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

As shown in Patent Document 2, memory retention characteristics can beimproved by doping of P (phosphorus) on a dielectric film. However,since Patent Document 2 relates to a method in which a dielectric filmis formed and then P (phosphorus) is doped on the formed dielectricfilm, there is a risk associated with non-uniform distribution ofdopants in the film or incorporation of impurities other than dopantsinto the film, and there is also a risk associated with the degradationof film quality of the dielectric film. Further, the operation may becomplicated due to multiple processes such as the heat treatmentprocess.

Further, as shown in Patent Document 3 to 5, techniques of addingvarious elements to improve characteristics of a dielectric film havebeen developed, but when a ferroelectric thin film is intended for usein a thin film capacitor with a high capacity density, it has been arequirement for balanced improvement of both leakage currentcharacteristics and dielectric strength voltage characteristics, i.e.reduction of leakage current and improvement of dielectric strengthvoltage, or improvement of specific permittivity.

Further, if a film thickness of the formed ferroelectric thin film isnot sufficient, this may result in a high leakage current density andthe occurrence of a dielectric breakdown, and therefore it is impossibleto sufficiently exert the performance as a capacitor.

Further, if a film thickness is excessively thick, sufficientcapacitance could not be obtained.

Further, if a film thickness of the formed ferroelectric thin film isdecreased in order to increase the capacitance, this may result in anincrease in leakage current density and consequently the occurrence ofdielectric breakdown, and therefore it is impossible to sufficientlyexert the performance as a capacitor. In addition, it cannot be saidthat an attempt of adding trace elements to increase the specificpermittivity is sufficiently carried out.

Further, Patent Document 4 describes the addition of various elements toa dielectric film, but the object thereof is to lower itscrystallization temperature and only the results of a residualpolarization value are described therein. In addition, in order tosecure a high specific permittivity necessary for use as a thin filmcapacitor having a high capacity density, there is no disclosure ofwhich element is used as a dopant for a dielectric film, and what amountof the dopant is added to contribute to improvement of the specificpermittivity.

An object of the present invention is to provide a composition for theformation of a ferroelectric thin film, which is suitable for use in athin film capacitor having a high capacity density, a method for forminga ferroelectric thin film, and a ferroelectric thin film formed by thesame method.

Another object of the present invention is to provide a composition forthe formation of a ferroelectric thin film, which is capable ofachieving a balanced improvement of both leakage current characteristicsand dielectric strength voltage characteristics, such as reduction ofleakage current and improvement of dielectric strength voltage, by asimplified method and which is suitable for use in a thin film capacitorhaving a high capacity density, a method for forming a ferroelectricthin film, and a ferroelectric thin film formed by the same method.

A further object of the present invention is to provide a compositionfor the formation of a ferroelectric thin film, which is capable ofachieving a specific permittivity equivalent to that of a conventionalferroelectric thin film and a lower leakage current density by asimplified method and which is suitable for use in a thin film capacitorhaving a high capacity density, a method for forming a ferroelectricthin film, and a ferroelectric thin film formed by the same method.

Yet another object of the present invention is to provide a compositionfor the formation of a ferroelectric thin film, which is capable ofsignificantly improving a specific permittivity as compared to aconventional ferroelectric thin film by a simplified method and which issuitable for use in a thin film capacitor having a high capacitydensity, a method for forming a ferroelectric thin film, and aferroelectric thin film formed by the same method.

Means for Solving the Problem

[Group 1]

A first embodiment of the present invention is a composition for theformation of a ferroelectric thin film which is used in the formation ofa ferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT, wherein the composition is a liquidcomposition for the formation of a thin film of a mixed composite metaloxide formed of a mixture of a composite metal oxide A represented bythe general formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z))O₃ [In theformula (1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide Bincluding one or more selected from the group consisting of P(phosphorus), Si, Ce, and Bi,

the composition including an organometallic compound solution whereinthe raw material constituting the composite metal oxide A and the rawmaterial constituting the composite oxide B are dissolved in an organicsolvent in such a proportion as to provide the metal atom ratiorepresented by the general formula (1).

The embodiment of A-1 of the present invention is a composition for theformation of a ferroelectric thin film which is used in the formation ofa ferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT, wherein the composition is a liquidcomposition for the formation of a thin film of a mixed composite metaloxide formed of a mixture of a composite metal oxide A represented bythe general formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In theformula (1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide Bincluding P (phosphorus),

the composition including an organometallic compound solution whereinthe raw material constituting the composite metal oxide A and the rawmaterial constituting the composite oxide B are dissolved in an organicsolvent in such a proportion as to provide the metal atom ratiorepresented by the general formula (1).

The embodiment of A-2 of the present invention is an invention based onthe embodiment of A-1, wherein the raw material constituting thecomposite metal oxide A is a compound whose organic radical is bound toa metal element through oxygen or nitrogen atoms thereof.

The embodiment of A-3 of the present invention is an invention based onthe embodiment of A-2, wherein the raw material constituting thecomposite metal oxide A is one or more selected from the groupconsisting of a metal alkoxide, a metal diol complex, a metal triolcomplex, a metal carboxylate, a metal β-diketonato complex, a metalβ-diketoester complex, a metal β-iminoketo complex, and a metal aminocomplex.

The embodiment of A-4 of the present invention is an invention based onthe embodiment of A-1, wherein the raw material constituting thecomposite oxide B is a compound whose organic radical is bound to a P(phosphorus) element through oxygen or nitrogen atoms thereof.

The embodiment of A-5 of the present invention is an invention based onthe embodiment of A-4, wherein the raw material constituting thecomposite oxide B is one or more selected from the group consisting ofan alkoxide compound, a diol compound, a triol compound, a carboxylatecompound, a β-diketonato compound, a β-diketoester compound, aβ-iminoketo compound, and an amino compound.

The embodiment of A-6 of the present invention is an invention based onany one of the embodiment of A-1 to the embodiment of A-5, furtherincluding one or more stabilizers selected from the group consisting ofβ-diketone, β-ketonic acid, β-ketoester, oxy-acid, diol, triol, highercarboxylic acid, alkanol amine and polyamine, in a proportion of 0.2 to3 mol per 1 mol of the total amount of metals in the composition.

The embodiment of A-7 of the present invention is an invention based onany one of the embodiment of A-1 to the embodiment of A-6, wherein themolar ratio B/A of the composite oxide B to the composite metal oxide Ais in the range of 0<B/A<0.2.

The embodiment of A-8 of the present invention is an invention based onthe embodiment of the embodiment of A-7, wherein the molar ratio B/A ofthe composite oxide B to the composite metal oxide A is in the range of0.003≦B/A≦0.1.

The embodiment of A-9 of the present invention is a method for forming aferroelectric thin film, including applying a ferroelectric thinfilm-forming composition based on any one of the embodiment of A-1 tothe embodiment of A-8 to a heat-resistant substrate; heating thesubstrate in air or under an oxidative atmosphere or watervapor-containing atmosphere, wherein the applying and the heating isperformed once or is repeated until the film reaches the desiredthickness; and baking the film at its crystallization temperature orhigher, at least during or after heating in the final step.

The embodiment of A-10 of the present invention is a ferroelectric thinfilm formed by a method based on the embodiment of A-9.

The embodiment of A-11 of the present invention is a compositeelectronic component of a thin-film condenser, a capacitor, an IPD(Integrated Passive Device), a DRAM memory condenser, a multilayercapacitor, a transistor gate insulator, a nonvolatile memory, apyroelectric infrared detection device, a piezoelectric device, anelectro-optical device, an actuator, a resonator, an ultrasonic motor,or an LC noise filter device which has a ferroelectric thin film basedon the embodiment of A-10.

The embodiment of A-12 of the present invention is a compositeelectronic component of a thin-film condenser, a capacitor, an IPD, aDRAM memory condenser, a multilayer capacitor, a transistor gateinsulator, a nonvolatile memory, a pyroelectric infrared detectiondevice, a piezoelectric device, an electro-optical device, an actuator,a resonator, an ultrasonic motor, or an LC noise filter device which hasa ferroelectric thin film based on the embodiment of A-11 andcorresponding to a frequency band of 100 MHz or higher.

The embodiment of B-1 of the present invention is a composition for theformation of a ferroelectric thin film which is used in the formation ofa ferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT, wherein the composition is a liquidcomposition for the formation of a thin film of a mixed composite metaloxide formed of a mixture of a composite metal oxide A represented bythe general formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In theformula (1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide B(composite metal oxide) including Si, the composition including anorganometallic compound solution wherein the raw material constitutingthe composite metal oxide A and the raw material constituting thecomposite oxide B (composite metal oxide) are dissolved in an organicsolvent in such a proportion as to provide the metal atom ratiorepresented by the general formula (1).

The embodiment of B-2 of the present invention is an invention based onthe embodiment of B-1, wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is a compound whose organic radical is bound to a metal elementthrough oxygen or nitrogen atoms thereof.

The embodiment of B-3 of the present invention is an invention based onthe embodiment of B-2, wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is one or more selected from the group consisting of a metalalkoxide, a metal diol complex, a metal triol complex, a metalcarboxylate, a metal β-diketonato complex, a metal β-diketoestercomplex, a metal β-iminoketo complex, and a metal amino complex.

The embodiment of B-4 of the present invention is an invention based onany one of the embodiment of B-1 to the embodiment of B-3, furtherincluding one or more stabilizers selected from the group consisting ofβ-diketone, β-ketonic acid, β-ketoester, oxy-acid, diol, triol, highercarboxylic acid, alkanol amine and polyamine, in a proportion of 0.2 to3 mol per 1 mol of the total amount of metals in the composition.

The embodiment of B-5 of the present invention is an invention based onany one of the embodiment of B-1 to the embodiment of B-4, wherein theorganic solvent is one or more selected from the group consisting ofcarboxylic acids, alcohols, esters, ketones, esters, cycloalkanes,aromatics and tetrahydrofurans.

The embodiment of B-6 of the present invention is an invention based onany one of the embodiment of B-1 to the embodiment of B-5, wherein theorganic solvent includes propylene glycol.

The embodiment of B-7 of the present invention is an invention based onany one of the embodiment of B-1 to the embodiment of B-6, wherein themolar ratio B/A of the composite oxide B (composite metal oxide) to thecomposite metal oxide A is in the range of 0<B/A<0.1.

The embodiment of B-8 of the present invention is an invention based onthe embodiment of B-7, the molar ratio B/A of the composite oxide B(composite metal oxide) to the composite metal oxide A is in the rangeof 0.005≦B/A≦0.05.

The embodiment of B-9 of the present invention is a method for forming aferroelectric thin film, including applying a ferroelectric thinfilm-forming composition based on any one of the embodiment of B-1 tothe embodiment of B-8 to a heat-resistant substrate; heating thesubstrate in air or under an oxidative atmosphere or watervapor-containing atmosphere, wherein the applying and the heating isperformed once or is repeated until the film reaches the desiredthickness; and baking the film at its crystallization temperature orhigher, at least during or after heating in the final step.

The embodiment of B-10 of the present invention is a ferroelectric thinfilm formed by a method based on the embodiment of B-9.

The embodiment of B-11 of the present invention is a compositeelectronic component of a thin-film condenser, a capacitor, an IPD(Integrated Passive Device), a DRAM memory condenser, a multilayercapacitor, a transistor gate insulator, a nonvolatile memory, apyroelectric infrared detection device, a piezoelectric device, anelectro-optical device, an actuator, a resonator, an ultrasonic motor,or an LC noise filter device which has a ferroelectric thin film basedon the embodiment of B-10.

The embodiment of B-12 of the present invention is a compositeelectronic component of a thin-film condenser, a capacitor, an IPD, aDRAM memory condenser, a multilayer capacitor, a transistor gateinsulator, a nonvolatile memory, a pyroelectric infrared detectiondevice, a piezoelectric device, an electro-optical device, an actuator,a resonator, an ultrasonic motor, or an LC noise filter device which hasa ferroelectric thin film based on the embodiment of B-11 andcorresponding to a frequency band of 100 MHz or higher.

The embodiment of C-1 of the present invention is a composition for theformation of a ferroelectric thin film which is used in the formation ofa ferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT, wherein the composition is a liquidcomposition for the formation of a thin film of a mixed composite metaloxide formed of a mixture of a composite metal oxide A represented bythe general formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In theformula (1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide B(composite metal oxide) including Ce, the composition including anorganometallic compound solution wherein the raw material constitutingthe composite metal oxide A and the raw material constituting thecomposite oxide B (composite metal oxide) are dissolved in an organicsolvent in such a proportion as to provide the metal atom ratiorepresented by the general formula (1).

The embodiment of C-2 of the present invention is an invention based onthe embodiment of C-1, wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is a compound whose organic radical is bound to a metal elementthrough oxygen or nitrogen atoms thereof.

The embodiment of C-3 of the present invention is an invention based onthe embodiment of C-2, wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is one or more selected from the group consisting of a metalalkoxide, a metal diol complex, a metal triol complex, a metalcarboxylate, a metal β-diketonato complex, a metal β-diketoestercomplex, a metal β-iminoketo complex, and a metal amino complex.

The embodiment of C-4 of the present invention is an invention based onany one of the embodiment of C-1 to the embodiment of C-3, furtherincluding one or more stabilizers selected from the group consisting ofβ-diketone, β-ketonic acid, β-ketoester, oxy-acid, diol, triol, highercarboxylic acid, alkanol amine and polyamine, in a proportion of 0.2 to3 mol per 1 mol of the total amount of metals in the composition.

The embodiment of C-5 of the present invention is an invention based onany one of the embodiment of C-1 to the embodiment of C-4, wherein themolar ratio B/A of the composite oxide B (composite metal oxide) to thecomposite metal oxide A is in the range of 0<B/A<0.05.

The embodiment of C-6 of the present invention is an invention based onthe embodiment of C-5, the molar ratio B/A of the composite oxide B(composite metal oxide) to the composite metal oxide A is in the rangeof 0.005≦B/A≦0.03.

The embodiment of C-7 of the present invention is a method for forming aferroelectric thin film, including applying a ferroelectric thinfilm-forming composition based on any one of the embodiment of C-1 tothe embodiment of C-6 to a heat-resistant substrate; heating thesubstrate in air or under an oxidative atmosphere or watervapor-containing atmosphere, wherein the applying and the heating isperformed once or is repeated until the film reaches the desiredthickness; and baking the film at its crystallization temperature orhigher, at least during or after heating in the final step.

The embodiment of C-8 of the present invention is a ferroelectric thinfilm formed by a method based on the embodiment of C-7.

The embodiment of C-9 of the present invention is a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD (IntegratedPassive Device), a DRAM memory condenser, a multilayer capacitor, atransistor gate insulator, a nonvolatile memory, a pyroelectric infrareddetection device, a piezoelectric device, an electro-optical device, anactuator, a resonator, an ultrasonic motor, or an LC noise filter devicewhich has a ferroelectric thin film based on the embodiment of C-8.

The embodiment of C-10 of the present invention is a compositeelectronic component of a thin-film condenser, a capacitor, an IPD, aDRAM memory condenser, a multilayer capacitor, a transistor gateinsulator, a nonvolatile memory, a pyroelectric infrared detectiondevice, a piezoelectric device, an electro-optical device, an actuator,a resonator, an ultrasonic motor, or an LC noise filter device which hasa ferroelectric thin film based on the embodiment of C-9 andcorresponding to a frequency band of 100 MHz or higher.

The embodiment of D-1 of the present invention is a composition for theformation of a ferroelectric thin film which is used in the formation ofa ferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT, wherein the composition is a liquidcomposition for the formation of a thin film of a mixed composite metaloxide formed of a mixture of a composite metal oxide A represented bythe general formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In theformula (1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide B(composite metal oxide) including Bi, the composition including anorganometallic compound solution wherein the raw material constitutingthe composite metal oxide A and the raw material constituting thecomposite oxide B (composite metal oxide) are dissolved in an organicsolvent in such a proportion as to provide the metal atom ratiorepresented by the general formula (1).

The embodiment of D-2 of the present invention is an invention based onthe embodiment of D-1, and is a composition for the formation of aferroelectric thin film wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is a compound whose organic radical is bound to a metal elementthrough oxygen or nitrogen atoms thereof.

The embodiment of D-3 of the present invention is an invention based onthe embodiment of D-2, and is a composition for the formation of aferroelectric thin film wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is one or more selected from the group consisting of a metalalkoxide, a metal diol complex, a metal triol complex, a metalcarboxylate, a metal β-diketonato complex, a metal β-diketoestercomplex, a metal β-iminoketo complex, and a metal amino complex.

The embodiment of D-4 of the present invention is an invention based onany one of the embodiment of D-1 to the embodiment of D-3, and is acomposition for the formation of a ferroelectric thin film furtherincluding one or more stabilizers selected from the group consisting ofβ-diketone, β-ketonic acid, β-ketoester, oxy-acid, diol, triol, highercarboxylic acid, alkanol amine and polyamine, in a proportion of 0.2 to3 mol per 1 mol of the total amount of metals in the composition.

The embodiment of D-5 of the present invention is an invention based onany one of the embodiment of D-1 to the embodiment of D-4, wherein themolar ratio B/A of the composite oxide B (composite metal oxide) to thecomposite metal oxide A is in the range of 0<B/A<0.2.

The embodiment of D-6 of the present invention is an invention based onthe embodiment of D-5, the molar ratio B/A of the composite oxide B(composite metal oxide) to the composite metal oxide A is in the rangeof 0.005≦B/A≦0.1.

The embodiment of D-7 of the present invention is a method for forming aferroelectric thin film, including applying a ferroelectric thinfilm-forming composition based on any one of the embodiment of D-1 tothe embodiment of D-6 to a heat-resistant substrate; heating thesubstrate in air or under an oxidative atmosphere or watervapor-containing atmosphere, wherein the applying and the heating isperformed once or is repeated until the film reaches the desiredthickness; and baking the film at its crystallization temperature orhigher, at least during or after heating in the final step.

The embodiment of D-8 of the present invention is a ferroelectric thinfilm formed by a method based on the embodiment of D-7.

The embodiment of D-9 of the present invention is a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD (IntegratedPassive Device), a DRAM memory condenser, a multilayer capacitor, atransistor gate insulator, a nonvolatile memory, a pyroelectric infrareddetection device, a piezoelectric device, an electro-optical device, anactuator, a resonator, an ultrasonic motor, or an LC noise filter devicewhich has a ferroelectric thin film based on the embodiment of D-8.

The embodiment of D-10 of the present invention is a compositeelectronic component of a thin-film condenser, a capacitor, an IPD, aDRAM memory condenser, a multilayer capacitor, a transistor gateinsulator, a nonvolatile memory, a pyroelectric infrared detectiondevice, a piezoelectric device, an electro-optical device, an actuator,a resonator, an ultrasonic motor, or an LC noise filter device which hasa ferroelectric thin film based on the embodiment of D-9 andcorresponding to a frequency band of 100 MHz or higher.

[Group 2]

An embodiment of Group 2 of the present invention is a composition forthe formation of a ferroelectric thin film which is used in theformation of a ferroelectric thin film of one material selected from thegroup consisting of PLZT, PZT, and PT, wherein the composition is aliquid composition for the formation of a thin film of a mixed compositemetal oxide formed of a mixture of a composite metal oxide A representedby the general formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In theformula (1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide Bincluding one or more selected from the group consisting of Sn, Sm, Nd,and Y (yttrium), the composition including an organometallic compoundsolution wherein the raw material constituting the composite metal oxideA and the raw material constituting the composite oxide B are dissolvedin an organic solvent in such a proportion as to provide the metal atomratio represented by the general formula (1), and in such a manner thatwhen the composite oxide B includes Sn, the molar ratio B/A of thecomposite oxide B to the composite metal oxide A is in the range of0.003≦B/A≦0.05, or when the composite oxide B includes one or moreselected from the group consisting of Sm, Nd, and Y (yttrium), the molarratio B/A of the composite oxide B to the composite metal oxide A is inthe range of 0.005≦B/A<0.03.

The embodiment of E-1 of the present invention is a composition for theformation of a ferroelectric thin film which is used in the formation ofa ferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT, wherein the composition is a liquidcomposition for the formation of a thin film of a mixed composite metaloxide formed of a mixture of a composite metal oxide A represented bythe general formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In theformula (1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide B(composite metal oxide) including Sn, the composition including anorganometallic compound solution wherein the raw material constitutingthe composite metal oxide A and the raw material constituting thecomposite oxide B (composite metal oxide) are dissolved in an organicsolvent in such a proportion as to provide the metal atom ratiorepresented by the general formula (1), and in such a manner that themolar ratio B/A of the composite oxide B to the composite metal oxide Ais in the range of 0.003≦B/A≦0.05.

The embodiment of E-2 of the present invention is an invention based onthe embodiment of E-1, wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is a compound whose organic radical is bound to a metal elementthrough oxygen or nitrogen atoms thereof.

The embodiment of E-3 of the present invention is an invention based onthe embodiment of E-2, wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is one or more selected from the group consisting of a metalalkoxide, a metal diol complex, a metal triol complex, a metalcarboxylate, a metal β-diketonato complex, a metal β-diketoestercomplex, a metal β-iminoketo complex, and a metal amino complex.

The embodiment of E-4 of the present invention is an invention based onany one of the embodiment of E-1 to the embodiment of E-3, furtherincluding one or more stabilizers selected from the group consisting ofβ-diketone, β-ketonic acid, β-ketoester, oxy-acid, diol, triol, highercarboxylic acid, alkanol amine and polyamine, in a proportion of 0.2 to3 mol per 1 mol of the total amount of metals in the composition.

The embodiment of E-5 of the present invention is a method for forming aferroelectric thin film, including applying a ferroelectric thinfilm-forming composition based on any one of the embodiment of E-1 tothe embodiment of E-4 to a heat-resistant substrate; heating thesubstrate in air or under an oxidative atmosphere or watervapor-containing atmosphere, wherein the applying and the heating isperformed once or is repeated until the film reaches the desiredthickness; and baking the film at its crystallization temperature orhigher, at least during or after heating in the final step.

The embodiment of E-6 of the present invention is a ferroelectric thinfilm formed by a method based on the embodiment of E-5.

The embodiment of E-7 of the present invention is a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD (IntegratedPassive Device), a DRAM memory condenser, a multilayer capacitor, atransistor gate insulator, a nonvolatile memory, a pyroelectric infrareddetection device, a piezoelectric device, an electro-optical device, anactuator, a resonator, an ultrasonic motor, or an LC noise filter devicewhich has a ferroelectric thin film based on the embodiment of E-6.

The embodiment of E-8 of the present invention is a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD, a DRAM memorycondenser, a multilayer capacitor, a transistor gate insulator, anonvolatile memory, a pyroelectric infrared detection device, apiezoelectric device, an electro-optical device, an actuator, aresonator, an ultrasonic motor, or an LC noise filter device which has aferroelectric thin film based on the embodiment of E-7 and correspondingto a frequency band of 100 MHz or higher.

The embodiment of F-1 of the present invention is a composition for theformation of a ferroelectric thin film which is used in the formation ofa ferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT, wherein the composition is a liquidcomposition for the formation of a thin film of a mixed composite metaloxide formed of a mixture of a composite metal oxide A represented bythe general formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In theformula (1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide B(composite metal oxide) including Sm, the composition including anorganometallic compound solution wherein the raw material constitutingthe composite metal oxide A and the raw material constituting thecomposite oxide B (composite metal oxide) are dissolved in an organicsolvent in such a proportion as to provide the metal atom ratiorepresented by the general formula (1), and in such a manner that themolar ratio B/A of B to A is in the range of 0.005≦B/A≦0.03.

The embodiment of F-2 of the present invention is an invention based onthe embodiment of F-1, and is a composition for the formation of aferroelectric thin film wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is a compound whose organic radical is bound to a metal elementthrough oxygen or nitrogen atoms thereof.

The embodiment of F-3 of the present invention is an invention based onthe embodiment of F-2, and is a composition for the formation of aferroelectric thin film wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is one or more selected from the group consisting of a metalalkoxide, a metal diol complex, a metal triol complex, a metalcarboxylate, a metal β-diketonato complex, a metal β-diketoestercomplex, a metal β-iminoketo complex, and a metal amino complex.

The embodiment of F-4 of the present invention is an invention based onany one of the embodiment of F-1 to the embodiment of F-3, and is acomposition for the formation of a ferroelectric thin film furtherincluding one or more stabilizers selected from the group consisting ofβ-diketone, β-ketonic acid, β-ketoester, oxy-acid, diol, triol, highercarboxylic acid, alkanol amine and polyamine, in a proportion of 0.2 to3 mol per 1 mol of the total amount of metals in the composition.

The embodiment of F-5 of the present invention is a method for forming aferroelectric thin film, including applying a ferroelectric thinfilm-forming composition based on any one of the embodiment of F-1 tothe embodiment of F-4 to a heat-resistant substrate; heating thesubstrate in air or under an oxidative atmosphere or watervapor-containing atmosphere, wherein the applying and the heating isperformed once or is repeated until the film reaches the desiredthickness; and baking the film at its crystallization temperature orhigher, at least during or after heating in the final step.

The embodiment of F-6 of the present invention is a ferroelectric thinfilm formed by a method based on the embodiment of F-5.

The embodiment of F-7 of the present invention is a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD (IntegratedPassive Device), a DRAM memory condenser, a multilayer capacitor, atransistor gate insulator, a nonvolatile memory, a pyroelectric infrareddetection device, a piezoelectric device, an electro-optical device, anactuator, a resonator, an ultrasonic motor, or an LC noise filter devicewhich has a ferroelectric thin film based on the embodiment of F-6.

The embodiment of F-8 of the present invention is a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD, a DRAM memorycondenser, a multilayer capacitor, a transistor gate insulator, anonvolatile memory, a pyroelectric infrared detection device, apiezoelectric device, an electro-optical device, an actuator, aresonator, an ultrasonic motor, or an LC noise filter device which has aferroelectric thin film based on the embodiment of F-7 and correspondingto a frequency band of 100 MHz or higher.

The embodiment of G-1 of the present invention is a composition for theformation of a ferroelectric thin film which is used in the formation ofa ferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT, wherein the composition is a liquidcomposition for the formation of a thin film of a mixed composite metaloxide formed of a mixture of a composite metal oxide A represented bythe general formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In theformula (1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide B(composite metal oxide) including Nd, the composition including anorganometallic compound solution wherein the raw material constitutingthe composite metal oxide A and the raw material constituting thecomposite oxide B (composite metal oxide) are dissolved in an organicsolvent in such a proportion as to provide the metal atom ratiorepresented by the general formula (1), and in such a manner that themolar ratio B/A of B to A is in the range of 0.005≦B/A≦0.03.

The embodiment of G-2 of the present invention is an invention based onthe embodiment of G-1, and is a composition for the formation of aferroelectric thin film wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is a compound whose organic radical is bound to a metal elementthrough oxygen or nitrogen atoms thereof.

The embodiment of G-3 of the present invention is an invention based onthe embodiment of G-2, and is a composition for the formation of aferroelectric thin film wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is one or more selected from the group consisting of a metalalkoxide, a metal diol complex, a metal triol complex, a metalcarboxylate, a metal β-diketonato complex, a metal β-diketoestercomplex, a metal β-iminoketo complex, and a metal amino complex.

The embodiment of G-4 of the present invention is an invention based onany one of the embodiment of G-1 to the embodiment of G-3, and is acomposition for the formation of a ferroelectric thin film furtherincluding one or more stabilizers selected from the group consisting ofβ-diketone, β-ketonic acid, β-ketoester, oxy-acid, diol, triol, highercarboxylic acid, alkanol amine and polyamine, in a proportion of 0.2 to3 mol per 1 mol of the total amount of metals in the composition.

The embodiment of G-5 of the present invention is a method for forming aferroelectric thin film, including applying a ferroelectric thinfilm-forming composition based on any one of the embodiment of G-1 tothe embodiment of G-4 to a heat-resistant substrate; heating thesubstrate in air or under an oxidative atmosphere or watervapor-containing atmosphere, wherein the applying and the heating isperformed once or is repeated until the film reaches the desiredthickness; and baking the film at its crystallization temperature orhigher, at least during or after heating in the final step.

The embodiment of G-6 of the present invention is a ferroelectric thinfilm formed by a method based on the embodiment of G-5.

The embodiment of G-7 of the present invention is a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD (IntegratedPassive Device), a DRAM memory condenser, a multilayer capacitor, atransistor gate insulator, a nonvolatile memory, a pyroelectric infrareddetection device, a piezoelectric device, an electro-optical device, anactuator, a resonator, an ultrasonic motor, or an LC noise filter devicewhich has a ferroelectric thin film based on the embodiment of G-6.

The embodiment of G-8 of the present invention is a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD, a DRAM memorycondenser, a multilayer capacitor, a transistor gate insulator, anonvolatile memory, a pyroelectric infrared detection device, apiezoelectric device, an electro-optical device, an actuator, aresonator, an ultrasonic motor, or an LC noise filter device which has aferroelectric thin film based on the embodiment of G-7 and correspondingto a frequency band of 100 MHz or higher.

The embodiment of H-1 of the present invention is a composition for theformation of a ferroelectric thin film which is used in the formation ofa ferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT, wherein the composition is a liquidcomposition for the formation of a thin film of a mixed composite metaloxide formed of a mixture of a composite metal oxide A represented bythe general formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In theformula (1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide B(composite metal oxide) including Y (yttrium), the composition includingan organometallic compound solution wherein the raw materialconstituting the composite metal oxide A and the raw materialconstituting the composite oxide B (composite metal oxide) are dissolvedin an organic solvent in such a proportion as to provide the metal atomratio represented by the general formula (1), and in such a manner thatthe molar ratio B/A of B to A is in the range of 0.005≦B/A≦0.03.

The embodiment of H-2 of the present invention is an invention based onthe embodiment of H-1, and is a composition for the formation of aferroelectric thin film wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is a compound whose organic radical is bound to a metal elementthrough oxygen or nitrogen atoms thereof.

The embodiment of H-3 of the present invention is an invention based onthe embodiment of H-2, and is a composition for the formation of aferroelectric thin film wherein the raw material constituting thecomposite metal oxide A and the composite oxide B (composite metaloxide) is one or more selected from the group consisting of a metalalkoxide, a metal diol complex, a metal triol complex, a metalcarboxylate, a metal β-diketonato complex, a metal β-diketoestercomplex, a metal β-iminoketo complex, and a metal amino complex.

The embodiment of H-4 of the present invention is an invention based onany one of the embodiment of H-1 to the embodiment of H-3, and is acomposition for the formation of a ferroelectric thin film furtherincluding one or more stabilizers selected from the group consisting ofβ-diketone, β-ketonic acid, β-ketoester, oxy-acid, diol, triol, highercarboxylic acid, alkanol amine and polyamine, in a proportion of 0.2 to3 mol per 1 mol of the total amount of metals in the composition.

The embodiment of H-5 of the present invention is a method for forming aferroelectric thin film, including applying a ferroelectric thinfilm-forming composition based on any one of the embodiment of H-1 tothe embodiment of H-4 to a heat-resistant substrate; heating thesubstrate in air or under an oxidative atmosphere or watervapor-containing atmosphere, wherein the applying and the heating isperformed once or is repeated until the film reaches the desiredthickness; and baking the film at its crystallization temperature orhigher, at least during or after heating in the final step.

The embodiment of H-6 of the present invention is a ferroelectric thinfilm formed by a method based on the embodiment of H-5.

The embodiment of H-7 of the present invention is a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD (IntegratedPassive Device), a DRAM memory condenser, a multilayer capacitor, atransistor gate insulator, a nonvolatile memory, a pyroelectric infrareddetection device, a piezoelectric device, an electro-optical device, anactuator, a resonator, an ultrasonic motor, or an LC noise filter devicewhich has a ferroelectric thin film based on the embodiment of H-6.

The embodiment of H-8 of the present invention is a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD, a DRAM memorycondenser, a multilayer capacitor, a transistor gate insulator, anonvolatile memory, a pyroelectric infrared detection device, apiezoelectric device, an electro-optical device, an actuator, aresonator, an ultrasonic motor, or an LC noise filter device which has aferroelectric thin film based on the embodiment of H-7 and correspondingto a frequency band of 100 MHz or higher.

[Group 3]

The embodiment of I-1 of the present invention is a composition for theformation of a ferroelectric thin film which is used in the formation ofa ferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT, wherein the composition is a liquidcomposition for the formation of a thin film of a composite metal oxideformed of a mixture of a composite metal oxide A represented by thegeneral formula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In the formula(1), 0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a carboxylic acid B which isrepresented by the general formula (2): C_(n)H_(2n+1)COOH (wherein3≦n≦7) and is capable of taking the structure of the following generalChemical Formula (3) upon coordination with the metal,

the composition including an organometallic compound solution whereinthe raw material constituting the composite metal oxide A, and thecarboxylic acid B are dissolved in an organic solvent in such a mannerthat the molar ratio B/A of the carboxylic acid B to the composite metaloxide A is in the range of 0<B/A<0.2.

In the Chemical Formula (3), within the range satisfying “n” of thegeneral formula (2): C_(n)H_(2n+1) COOH, R1, R2, R3, R4, R5, and R6represent hydrogen, a methyl group or an ethyl group, M represents Pb,La, Zr or Ti, and m represents a valence of M.

The embodiment of I-2 of the present invention is an invention based onthe embodiment of I-1, and is a composition for the formation of aferroelectric thin film wherein the raw material constituting thecomposite metal oxide A is a compound whose organic radical is bound toa metal element through oxygen or nitrogen atoms thereof.

The embodiment of I-3 of the present invention is an invention based onthe embodiment of I-2, and is a composition for the formation of aferroelectric thin film wherein the raw material constituting thecomposite metal oxide A is one or more selected from the groupconsisting of a metal alkoxide, a metal diol complex, a metal triolcomplex, a metal carboxylate, a metal β-diketonato complex, a metalβ-diketoester complex, a metal β-iminoketo complex, and a metal aminocomplex.

The embodiment of I-4 of the present invention is an invention based onany one of the embodiment of I-1 to the embodiment of I-3, and is acomposition for the formation of a ferroelectric thin film furtherincluding one or more stabilizers selected from the group consisting ofβ-diketone, β-ketonic acid, β-ketoester, oxy-acid, diol, triol, highercarboxylic acid, alkanol amine and polyamine, in a proportion of 0.2 to3 mol per 1 mol of the total amount of metals in the composition.

The embodiment of I-5 of the present invention is an invention based onany one of the embodiment of I-1 to the embodiment of I-4, wherein themolar ratio B/A of the carboxylic acid B to the composite metal oxide Ais in the range of 0.001≦B/A≦0.1.

The embodiment of I-6 of the present invention is an invention based onthe embodiment of I-5, wherein the molar ratio B/A of the carboxylicacid B to the composite metal oxide A is in the range of 0.03≦B/A≦0.1.

The embodiment of I-7 of the present invention is an invention based onthe embodiment of I-6, wherein the molar ratio B/A of the carboxylicacid B to the composite metal oxide A is in the range of 0.05≦B/A≦0.1.

The embodiment of I-8 of the present invention is a method for forming aferroelectric thin film, including applying a ferroelectric thinfilm-forming composition based on any one of the embodiment of I-1 tothe embodiment of I-7 to a heat-resistant substrate; heating thesubstrate in air or under an oxidative atmosphere or watervapor-containing atmosphere, wherein the applying and the heating isperformed once or is repeated until the film reaches the desiredthickness; and baking the film at its crystallization temperature orhigher, at least during or after heating in the final step.

The embodiment of I-9 of the present invention is a ferroelectric thinfilm formed by a method based on the embodiment of I-8.

The embodiment of I-10 of the present invention is a compositeelectronic component of a thin-film condenser, a capacitor, an IPD(Integrated Passive Device), a DRAM memory condenser, a multilayercapacitor, a transistor gate insulator, a nonvolatile memory, apyroelectric infrared detection device, a piezoelectric device, anelectro-optical device, an actuator, a resonator, an ultrasonic motor,or an LC noise filter device which has a ferroelectric thin film basedon the embodiment of I-9.

The embodiment of I-11 of the present invention is a compositeelectronic component of a thin-film condenser, a capacitor, an IPD, aDRAM memory condenser, a multilayer capacitor, a transistor gateinsulator, a nonvolatile memory, a pyroelectric infrared detectiondevice, a piezoelectric device, an electro-optical device, an actuator,a resonator, an ultrasonic motor, or an LC noise filter device which hasa ferroelectric thin film based on the embodiment of I-10 andcorresponding to a frequency band of 100 MHz or higher.

EFFECTS OF THE INVENTION

Through the formation of a ferroelectric thin film using a compositionfor the formation of a ferroelectric thin film in accordance with thepresent invention, it is possible to obtain a ferroelectric thin filmwhich is suitable for use in a thin film capacitor having a highcapacity density, in a simple manner.

As another effect of the present invention, through the formation of aferroelectric thin film using a composition for the formation of aferroelectric thin film in accordance with the present invention, it ispossible to obtain a ferroelectric thin film with balanced improvementof both leakage current characteristics and dielectric strength voltagecharacteristics, such as reduction of leakage current and improvement ofdielectric strength voltage, which is suitable for use in a thin filmcapacitor having a high capacity density, by a simplified method.

As another effect of the present invention, through the formation of aferroelectric thin film using a composition for the formation of aferroelectric thin film in accordance with the present invention, it ispossible to obtain a ferroelectric thin film which is capable ofachieving a specific permittivity equivalent to that of a conventionalferroelectric thin film and a lower leakage current density and which issuitable for use in a thin film capacitor having a high capacitydensity, by a simplified method. Accordingly, when it is configured tohave a leakage current density equivalent to that of the conventionalart, the thickness of the film can be further reduced and therefore ahigher specific permittivity can be obtained.

As another effect of the present invention, through the formation of aferroelectric thin film using a composition for the formation of aferroelectric thin film in accordance with the present invention, it ispossible to obtain a ferroelectric thin film which has a significantlyimproved specific permittivity as compared to a conventionalferroelectric thin film and which is suitable for use in a thin filmcapacitor having a high capacity density, by a simplified method.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the relationship between the leakage currentdensity and the P (phosphorus) additive amount, upon application of 5 Vin Example A-1 to Example A-29, and Comparative Example A-1 toComparative Example A-8.

FIG. 2 is a view showing the relationship between the leakage currentdensity and the P (phosphorus) additive amount, upon application of 20 Vin Example A-1 to Example A-29, and Comparative Example A-1 toComparative Example A-8.

FIG. 3 is a view showing the relationship between the leakage currentdensity and the P (phosphorus) additive amount, upon application of 50 Vin Example A-1 to Example A-29, and Comparative Example A-1 toComparative Example A-8.

FIG. 4 is a view showing the relationship between the dielectricstrength voltage and the P (phosphorus) additive amount, in Example A-1to Example A-29, and Comparative Example A-1 to Comparative Example A-8.

FIG. 5 is an I-V characteristic diagram of a thin film obtained inExample B-3.

FIG. 6 is an I-V characteristic diagram of a thin film obtained inExample B-8.

FIG. 7 is an I-V characteristic diagram of a thin film obtained inExample B-13.

FIG. 8 is an I-V characteristic diagram of a thin film obtained inExample B-18.

FIG. 9 is an I-V characteristic diagram of a thin film obtained inExample B-23.

FIG. 10 is an I-V characteristic diagram of a thin film obtained inComparative Example B-1.

FIG. 11 is an I-V characteristic diagram of a thin film obtained inComparative Example B-2.

FIG. 12 is a view showing the relationship between the specificpermittivity εr and the Sn additive amount in Example E-1 to ExampleE-8, and Comparative Example E-1.

FIG. 13 is a view showing a C-V curve in Comparative Example E-1.

FIG. 14 is a view showing a C-V curve in Example E-2.

FIG. 15 is a view showing a C-V curve in Example E-7.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments for carrying out the present invention will bedescribed.

[Group 1]

The composition for the formation of a ferroelectric thin film in Group1 of the present invention is a composition for the formation of aferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT. A ferroelectric thin film formed usingthis composition is in the form of a mixed composite metal oxide formedof a mixture of a composite metal oxide A represented by the generalformula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In the formula (1),0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide B including oneor more selected from the group consisting of P (phosphorus), Si, Ce,and Bi. In addition, the film-forming material is PLZT when y≠0 and z≠0in the formula (1), the film-forming material is PZT when y=0 and z≠0,and the film-forming material is PT when y=0 and z=0. The composition iscomposed of an organometallic compound solution wherein the raw materialconstituting the composite metal oxide A and the raw materialconstituting the composite oxide B are dissolved in an organic solventin such a proportion as to provide the metal atom ratio represented bythe general formula (1).

When the composite oxide B contains one or more selected from the groupconsisting of Si, Ce and Bi, the composite oxide B is a composite metaloxide.

When the composite oxide B contains P (phosphorus), the raw material forthe composite metal oxide A is preferably a compound whose organicradical is bound to each metal element of Pb, La, Zr and Ti throughoxygen or nitrogen atoms thereof. For example, such a compound isexemplified by one or more selected from the group consisting of a metalalkoxide, a metal diol complex, a metal triol complex, a metalcarboxylate, a metal β-diketonato complex, a metal β-diketoestercomplex, a metal β-iminoketo complex, and a metal amino complex. Theparticularly preferred compound is a metal alkoxide, a partialhydrolysate thereof, or an organic acid salt thereof. Among them,examples of the Pb compound and the La compound include organic acidsalts such as acetic acid salts (lead acetate, lanthanum acetate), andalkoxides such as lead diisopropoxide. Examples of the Ti compoundinclude alkoxides such as titanium tetraethoxide, titaniumtetraisopropoxide, titanium tetrabutoxide, and titanium dimethoxydiisopropoxide. Examples of the Zr compound preferably include alkoxidesas in the Ti compound. The metal alkoxide may be used without furtherprocessing, or may be used in the form of a partial hydrolysate thereoffor the purpose of facilitating the decomposition thereof.

When the composite oxide B contains P (phosphorus), the raw material forthe composite oxide B is preferably a compound whose organic radical isbound to a P (phosphorus) element through oxygen or nitrogen atomsthereof. For example, such a compound is exemplified by one or moreselected from the group consisting of an alkoxide compound, a diolcompound, a triol compound, a carboxylate compound, a β-diketonatocompound, a β-diketoester compound, a β-iminoketo compound, and an aminocompound. The particularly preferred compound is an alkoxide compound ora partial hydrolysate thereof.

When the composite oxide B is a composite metal oxide containing one ormore selected from the group consisting of Si, Ce and Bi, the rawmaterial for the composite metal oxide A and the raw material for thecomposite oxide B is preferably a compound whose organic radical isbound to each metal element of Pb, La, Zr, Ti, Si, Ce and Bi throughoxygen or nitrogen atoms thereof. For example, such a compound isexemplified by one or more selected from the group consisting of a metalalkoxide, a metal diol complex, a metal triol complex, a metalcarboxylate, a metal β-diketonato complex, a metal β-diketoestercomplex, a metal β-iminoketo complex, and a metal amino complex. Theparticularly preferred compound is a metal alkoxide, a partialhydrolysate thereof, or an organic acid salt thereof. Among them,examples of the Pb compound and the La compound include organic acidsalts such as acetic acid salts (lead acetate, lanthanum acetate), andalkoxides such as lead diisopropoxide. Examples of the Si compoundinclude organic acid salts such as silicon 2-ethyl hexanoate and silicon2-ethyl butyrate, alkoxides such as silicon tetraethoxide and silicontetra-n-butoxide, and metal β-diketonato complexes such astetrakis(acetylacetonate) silicon. Examples of the Ce compound includeorganic acid salts such as cerium 2-ethyl hexanoate and cerium 2-ethylbutyrate, alkoxides such as cerium tri-n-butoxide and ceriumtriethoxide, and metal β-diketonato complex such astris(acetylacetonate) cerium. Examples of the Bi compound includeorganic acid salts such as bismuth 2-ethyl hexanoate and bismuth 2-ethylbutyrate, alkoxides such as bismuth triisopropoxide and bismuthtri-t-pentoxide, and metal β-diketonato complexes such as tetra(methylheptanedionate)bismuth. Examples of the Ti compound include alkoxidessuch as titanium tetraethoxide, titanium tetraisopropoxide, titaniumtetrabutoxide, and titanium dimethoxy diisopropoxide. Examples of the Zrcompound preferably include alkoxides as in the Ti compound. The metalalkoxide may be used without further processing, or may be used in theform of a partial hydrolysate thereof for the purpose of facilitatingthe decomposition thereof.

In order to prepare the composition for the formation of a ferroelectricthin film in accordance with the present invention, these raw materialsare dissolved in a suitable solvent at the ratio corresponding to adesired ferroelectric thin film composition, thereby preparing asolution at a concentration suitable for application.

When the composite oxide B contains P (phosphorus), the molar ratio B/Aof the composite oxide B to the composite metal oxide A is adjusted tobe in the range of 0<B/A<0.2. If the molar ratio B/A is within theabove-specified range, it is possible to achieve balanced improvement ofboth leakage current characteristics and dielectric strength voltagecharacteristics of a ferroelectric thin film, i.e. reduction of leakagecurrent and improvement of dielectric strength voltage which are theeffects of the present invention. On the other hand, if the molar ratioB/A is higher than the upper limit, this results in problems associatedwith the degradation of a specific permittivity. Particularly preferredis the range of 0.003≦B/A≦0.1.

When the composite oxide B contains Si, the molar ratio B/A of thecomposite oxide B to the composite metal oxide A is adjusted to be inthe range of 0<B/A<0.1. If the molar ratio B/A is within theabove-specified range, it is possible to achieve a low leakage currentdensity and a high dielectric strength voltage which are the effects ofthe present invention. Particularly preferred is the range of0.005≦B/A≦0.05.

When the composite oxide B contains Ce, the molar ratio B/A of thecomposite oxide B to the composite metal oxide A is adjusted to be inthe range of 0<B/A<0.05. If the molar ratio B/A is within theabove-specified range, it is possible to achieve a specific permittivityequivalent to that of a conventional ferroelectric thin film, and a lowleakage current density, which are the effects of the present invention.On the other hand, if the molar ratio B/A is higher than the upperlimit, this results in inconveniences associated with the degradation ofa specific permittivity. Particularly preferred is the range of0.005≦B/A≦0.03.

When the composite oxide B contains Bi, the molar ratio B/A of thecomposite oxide B to the composite metal oxide A is adjusted to be inthe range of 0<B/A<0.2. If the molar ratio B/A is within theabove-specified range, it is possible to significantly improve thespecific permittivity as compared to a conventional ferroelectric thinfilm. On the other hand, if the molar ratio B/A is lower than the lowerlimit or higher than the upper limit, there is no significant differenceas compared to no addition of bismuth, so it is not suitable for use ina thin film capacitor having a high capacity density. Particularlypreferred is the range of 0.005≦B/A≦0.1.

Although the solvent for a composition for the formation of aferroelectric thin film used in Group 1 is appropriately determineddepending on the type of the raw materials to be used, there may begenerally used carboxylic acid, alcohol, ester, ketones (for example,acetone, methyl ethyl ketone), ethers (for example, dimethyl ether,diethyl ether), cycloalkanes (for example, cyclohexane, cyclohexanol),aromatics (for example, benzene, toluene, xylene), tetrahydrofuran, or amixed solvent of two or more thereof. When the composite oxide Bcontains Si, propylene glycol may be used.

As the carboxylic acid, specifically, it is preferred to use n-butyricacid, α-methyl butyric acid, i-valeric acid, 2-ethyl butyric acid,2,2-dimethyl butyric acid, 3,3-dimethyl butyric acid, 2,3-dimethylbutyric acid, 3-methyl pentanoic acid, 4-methyl pentanoic acid, 2-ethylpentanoic acid, 3-ethyl pentanoic acid, 2,2-dimethyl pentanoic acid,3,3-dimethyl pentanoic acid, 2,3-dimethyl pentanoic acid, 2-ethylhexanoic acid, or 3-ethyl hexanoic acid.

As the ester, it is preferred to use ethyl acetate, propyl acetate,n-butyl acetate, sec-butyl acetate, tert-butyl acetate, isobutylacetate, n-amyl acetate, sec-amyl acetate, tert-amyl acetate, or isoamylacetate. As the alcohol, it is preferred to use 1-propanol, 2-propanol,1-butanol, 2-butanol, iso-butyl alcohol, 1-pentanol, 2-pentanol,2-methyl-2-pentanol, or 2-methoxy ethanol.

In addition, the total concentration of an organometallic compound in anorganometallic compound solution of the composition for the formation ofa ferroelectric thin film is preferably in the range of 0.1 to 20% bymass, in terms of the metal oxides.

The organometallic compound solution may contain, if necessary, astabilizer selected from the group consisting of β-diketones (forexample, acetylacetone, heptafluorobutanoyl pyvaloyl methane, dipyvaloylmethane, trifluoro acetylacetone, benzoyl acetone, etc.), β-ketonicacids (for example, acetoacetic acid, propionyl acetic acid, benzoylacetic acid, etc.), β-ketoesters (for example, lower alkyl esters suchas methyl, propyl, butyl esters and the like of the above-mentionedketonic acids), oxy-acids (for example, lactic acid, glycolic acid,α-oxy butyric acid, salicylic acid, etc.), lower alkyl esters of theabove-mentioned oxy-acids, oxy ketones (for example, diacetone alcohol,acetoin, etc.), diol, triol, higher carboxylic acid, alkanol amines (forexample, diethanolamine, triethanolamine, monoethanolamine), andpolyamine, in a proportion of 0.2 to 3 (in terms of number of stabilizermolecules)/(number of metal atoms).

In the present invention, the above-prepared organometallic compoundsolution is preferably subjected to filtration or the like to removeparticles, such that the number of particles having a particle diameterof 0.5 μm or more (particularly 0.3 μm or more, and more particularly0.2 μm or more) is 50 particles/mL or less per 1 mL of the solution.

Further, the number of particles in the corresponding organometalliccompound solution is measured using a light scattering particle counter.

If the number of particles having a particle diameter of 0.5 μm or morein the organometallic compound solution is higher than 50 particles/mL,the long-term storage stability is deteriorated. The smaller number ofparticles having a particle diameter of 0.5 μm or more in theorganometallic compound solution is preferable. Particularly preferredis 30 particles/mL or less.

Although there is no particular limitation to the method of treating anorganometallic compound solution to achieve the above-mentioned particlenumber after preparation thereof, for example, the following methods maybe employed. The first method is a filtration method of transferring asolution to a syringe, using a commercially available membrane filterhaving a pore diameter of 0.2 μm. The second method is a pressurefiltration method with combination of a commercially available membranefilter having a pore diameter of 0.05 μm and a pressurized tank. Thethird method is a cycle filtration with combination of the filter usedin the second method and a solution circulation bath.

In any one of the above methods, the particle capture rate of the filtervaries depending on the solution transfer pressure. It is generallyknown that lower pressure leads to a higher capture rate. In particular,with regard to the first and second methods, in order to achieve thecondition that the number of particles having a particle diameter of 0.5μm or more is 50 or less, the solution is preferably passed through afilter at a very low rate under a low pressure.

By using the composition for the formation of a ferroelectric thin filmin accordance with the present invention, it is possible to convenientlyform a ferroelectric thin film in the form of a mixed composite metaloxide formed of a mixture of a composite metal oxide A of one materialselected from the group consisting of PLZT, PZT, and PT with a compositeoxide B including one or more selected from the group consisting of P(phosphorus), Si, Ce, and Bi.

In order to prepare a ferroelectric thin film using the composition forthe formation of a ferroelectric thin film in accordance with thepresent invention, the above composition is applied to a heat-resistantsubstrate by an application method such as spin coating, dip coating, orLSMCD (Liquid Source Misted Chemical Deposition), followed by drying(pre-baking) and main baking.

Specific examples of the heat-resistant substrate that can be usedherein include, but are not limited to, substrates whose substratesurface part employs a perovskite-type conductive oxide such assingle-crystalline Si, polycrystalline Si, Pt, Pt (uppermost layer)/Ti,Pt (uppermost layer)/Ta, Ru, RuO₂, Ru (uppermost layer)/RuO₂, RuO₂(uppermost layer)/Ru, Ir, IrO₂, Ir (uppermost layer)/IrO₂, Pt(uppermostlayer)/Ir, Pt (uppermost layer)/IrO₂, SrRuO₃ or (La_(x)Sr_((1−x))) CoO₃.

In addition, when a desired film thickness cannot be obtained by onetime of application, the application and drying processes are repeatedseveral times, and then main baking is carried out. As used herein, theterm “desired film thickness” refers to a thickness of the ferroelectricthin film which is obtained after the main baking. For use in a thinfilm capacitor with a high capacity density, a film thickness of theferroelectric thin film after the main baking is in the range of 50 to500 nm.

Further, since the pre-baking is carried out for the removal of thesolvent and for the conversion of an organometallic compound or organiccompound into a composite oxide by pyrolysis or hydrolysis, thepre-baking is carried out in air or under an oxidative atmosphere orwater vapor-containing atmosphere. Also with regard to heating in air,moisture necessary for hydrolysis is sufficiently secured from moisturein air. The heating may be carried out in two steps, i.e.low-temperature heating for the removal of the solvent andhigh-temperature heating for the decomposition of the organometalliccompound or organic compound.

The main baking is a process for baking to crystallize the thin filmobtained by the pre-baking at a temperature equal to or higher than itscrystallization temperature. Thereby, a ferroelectric thin film can beobtained. A baking atmosphere for this crystallization process ispreferably O₂, N₂, Ar, N₂O or H₂, or a mixed gas thereof.

When the composite oxide B contains P (phosphorus), the pre-baking iscarried out at a temperature of 150 to 550° C. for 1 to 30 minutes, andthe main baking is carried out at a temperature of 450 to 800° C. for 1to 10 minutes. The main baking may also be carried out by rapid thermalannealing (RTA treatment). When the main baking is carried out by RTAtreatment, the temperature elevation rate is preferably in the range of10 to 100° C./sec.

When the composite oxide B contains one or more selected from the groupconsisting of Si, Ce and Bi, the pre-baking is carried out at atemperature of 150 to 550° C. for 5 to 10 minutes, and the main bakingis carried out at a temperature of 450 to 800° C. for 1 to 60 minutes.The main baking may also be carried out by rapid thermal annealing (RTAtreatment). When the main baking is carried out by RTA treatment, thetemperature elevation rate is preferably in the range of 10 to 100°C./sec.

When the composite oxide B contains P (phosphorus), the thus formedferroelectric thin film of the present invention exhibits balancedimprovement of both leakage current characteristics and dielectricstrength voltage characteristics, i.e. reduction of leakage current andimprovement of dielectric strength voltage, has excellent basiccharacteristics as a capacitor, and is very suitable for use in a thinfilm capacitor with a high capacity density. Further, the ferroelectricthin film of the present invention is excellent in basic characteristicsas IPD.

When the composite oxide B contains Si, the thus formed ferroelectricthin film of the present invention can achieve a lower leakage currentdensity and a higher dielectric strength voltage as compared to aconventional ferroelectric thin film, and is therefore very suitable foruse in a thin film capacitor. Accordingly, when it is configured to havea leakage current density equivalent to that of a conventionalferroelectric thin film, the thickness of the film can be furtherreduced, a higher capacity density can be obtained, and basiccharacteristics as a capacitor are excellent. In addition, thicknessreduction of the film has another advantage in that the amount of rawmaterials to be used can also be reduced. Further, the ferroelectricthin film of the present invention is also excellent in basiccharacteristics as IPD.

When the composite oxide B contains Ce, the thus formed ferroelectricthin film of the present invention can achieve a specific permittivityequivalent to that of a conventional ferroelectric thin film and a lowleakage current density, and is therefore very suitable for use in athin film capacitor having a high capacity density. Accordingly, when itis configured to have a leakage current density equivalent to that of aconventional ferroelectric thin film, the thickness of the film can befurther reduced, a higher capacity density can be obtained, and basiccharacteristics as a capacitor are excellent. In addition, thicknessreduction of the film has another advantage in that the amount of rawmaterials to be used can also be reduced. Further, the ferroelectricthin film of the present invention is also excellent in basiccharacteristics as IPD.

When the composite oxide B contains Bi, the thus formed ferroelectricthin film of the present invention has a significantly improved specificpermittivity as compared to a conventional ferroelectric thin film andis excellent in basic characteristics as a capacitor, and is thereforepreferable for use in a thin film capacitor having a high capacitydensity. Further, the ferroelectric thin film of the present inventionis also excellent in basic characteristics as IPD.

Further, the ferroelectric thin film of Group 1 can be used as aconstituent material for a composite electronic component of a thin-filmcondenser, a capacitor, an IPD, a DRAM memory condenser, a multilayercapacitor, a transistor gate insulator, a nonvolatile memory, apyroelectric infrared detection device, a piezoelectric device, anelectro-optical device, an actuator, a resonator, an ultrasonic motor,or an LC noise filter device. In particular, the ferroelectric thin filmof Group 1 can be used in the composite electronic component whichcorresponds to a frequency band of 100 MHz or higher.

[Group 2]

The composition for the formation of a ferroelectric thin film in Group2 of the present invention is a composition for the formation of aferroelectric thin film of one material selected from the groupconsisting of PLZT, PZT, and PT. A ferroelectric thin film formed usingthis composition is in the form of a mixed composite metal oxide formedof a mixture of a composite metal oxide A represented by the generalformula (1): (Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In the formula (1),0.9<x<1.3, 0≦y<0.1, and 0≦z<0.9] with a composite oxide B (compositemetal oxide) including one or more selected from the group consisting ofSn, Sm, Nd and Y (yttrium). In addition, the film-forming material isPLZT when y≠0 and z≠0 in the formula (1), the film-forming material isPZT when y=0 and z≠0, and the film-forming material is PT when y=0 andz=0.

When the composite oxide B contains Sn, the composition is composed ofan organometallic compound solution wherein the raw materialconstituting the composite metal oxide A and the raw materialconstituting the composite oxide B (composite metal oxide) are dissolvedin an organic solvent in such a proportion as to provide the metal atomratio represented by the general formula (1), and in such a manner thatthe molar ratio B/A of the composite oxide B (composite metal oxide) tothe composite metal oxide A is in the range of 0.003≦B/A≦0.05, andparticularly preferably 0.006≦B/A≦0.04. If the molar ratio B/A is withinthe above-specified range, it is possible to significantly improve thespecific permittivity as compared to a conventional ferroelectric thinfilm. On the other hand, if the molar ratio B/A is lower than the lowerlimit or higher than the upper limit, there is no significant differenceas compared to no addition of tin, so it is not suitable for use in athin film capacitor having a high capacity density.

When the composite oxide B contains one or more selected from the groupconsisting of Sm, Nd and Y (yttrium), the composition is composed of anorganometallic compound solution wherein the raw material constitutingthe composite metal oxide A and the raw material constituting thecomposite oxide B (composite metal oxide) are dissolved in an organicsolvent in such a proportion as to provide the metal atom ratiorepresented by the general formula (1), and in such a manner that themolar ratio B/A of the composite oxide B to the composite metal oxide Ais in the range of 0.005≦B/A<0.03, and particularly preferably0.005≦B/A≦0.02. If the molar ratio B/A is within the above-specifiedrange, it is possible to significantly improve the specific permittivityas compared to a conventional ferroelectric thin film. On the otherhand, if the molar ratio B/A is lower than the lower limit or higherthan the upper limit, there is no significant difference as compared tono addition of two or more selected from the group consisting ofsamarium, neodymium and yttrium, so it is not suitable for use in a thinfilm capacitor having a high capacity density.

When the composite oxide B contains one or more selected from the groupconsisting of Sn, Sm, Nd and Y (yttrium), the composite oxide B is acomposite metal oxide.

The raw material for the composite metal oxide A and the raw materialfor the composite oxide B (composite metal oxide) are preferably acompound whose organic radical is bound to each metal element of Pb, La,Zr, Ti, Sn, Sm, Nd and Y (yttrium) through oxygen or nitrogen atomsthereof. For example, the raw material for the composite metal oxide isone or more selected from the group consisting of a metal alkoxide, ametal diol complex, a metal triol complex, a metal carboxylate, a metalβ-diketonato complex, a metal β-diketoester complex, a metal β-iminoketocomplex, and a metal amino complex. The particularly preferred compoundis a metal alkoxide, a partial hydrolysate thereof, or an organic acidsalt thereof.

Among them, examples of the Pb compound and the La compound includeorganic acid salts such as acetic acid salts (lead acetate, lanthanumacetate), and alkoxides such as lead diisopropoxide. Examples of the Sncompound include organic acid salts such as acetate(tin acetate),nitrate (tin nitrate), and tin octylate, and alkoxides such as tintetra-n-butoxide, and tin ethoxide.

Examples of the Sm compound include organic acid salts such as 2-ethylhexanoate (samarium 2-ethyl hexanoate), and 2-ethyl butyrate (samarium2-ethyl butyrate), alkoxides such as samarium tetra n-butoxide, andsamarium ethoxide, and metal β-diketonato complexes such astris(acetylacetonate).

Examples of the Nd compound include organic acid salts such as 2-ethylhexanoate (neodymium 2-ethyl hexanoate), and 2-ethyl butyrate (neodymium2-ethyl butyrate), alkoxides such as neodymium tetra n-butoxide, andneodymium ethoxide, and metal β-diketonato complexes such astris(acetylacetonate).

Examples of the Y (yttrium) compound include organic acid salts such as2-ethyl hexanoate (yttrium 2-ethyl hexanoate), and 2-ethyl butyrate(yttrium 2-ethyl butyrate), alkoxides such as yttrium tri-n-butoxide,and yttrium ethoxide, and metal β-diketonato complexes such astris(acetylacetonate).

Examples of the Ti compound include alkoxides such as titaniumtetraethoxide, titanium tetraisopropoxide, titanium tetrabutoxide, andtitanium dimethoxy diisopropoxide.

Examples of the Zr compound preferably include alkoxides as in the Ticompound. The metal alkoxide may be used without further processing, ormay be used in the form of a partial hydrolysate thereof for the purposeof facilitating the decomposition thereof.

In order to prepare the composition for the formation of a ferroelectricthin film in accordance with the present invention, these raw materialsare dissolved in a suitable solvent at the ratio corresponding to adesired ferroelectric thin film composition, thereby preparing asolution at a concentration suitable for application.

Although the solvent for a composition for the formation of aferroelectric thin film used herein is appropriately determineddepending on the type of the raw materials to be used, there may begenerally used a carboxylic acid, alcohol, ester, ketones (for example,acetone, methyl ethyl ketone), ethers (for example, dimethyl ether,diethyl ether), cycloalkanes (for example, cyclohexane, cyclohexanol),aromatics (for example, benzene, toluene, xylene), tetrahydrofuran, or amixed solvent of two or more thereof.

As the carboxylic acid, specifically, it is preferred to use n-butyricacid, α-methyl butyric acid, i-valeric acid, 2-ethyl butyric acid,2,2-dimethyl butyric acid, 3,3-dimethyl butyric acid, 2,3-dimethylbutyric acid, 3-methyl pentanoic acid, 4-methyl pentanoic acid, 2-ethylpentanoic acid, 3-ethyl pentanoic acid, 2,2-dimethyl pentanoic acid,3,3-dimethyl pentanoic acid, 2,3-dimethyl pentanoic acid, 2-ethylhexanoic acid, or 3-ethyl hexanoic acid.

As the ester, it is preferred to use ethyl acetate, propyl acetate,n-butyl acetate, sec-butyl acetate, tert-butyl acetate, isobutylacetate, n-amyl acetate, sec-amyl acetate, tert-amyl acetate, or isoamylacetate. As the alcohol, it is preferred to use 1-propanol, 2-propanol,1-butanol, 2-butanol, iso-butyl alcohol, 1-pentanol, 2-pentanol,2-methyl-2-pentanol, or 2-methoxy ethanol.

In addition, the total concentration of an organometallic compound in anorganometallic compound solution of the composition for the formation ofa ferroelectric thin film is preferably in the range of 0.1 to 20% byweight, in terms of the metal oxides.

The organometallic compound solution may contain, if necessary, astabilizer selected from the group consisting of β-diketones (forexample, acetylacetone, heptafluorobutanoyl pyvaloyl methane, dipyvaloylmethane, trifluoro acetylacetone, benzoyl acetone, etc.), β-ketonicacids (for example, acetoacetic acid, propionyl acetic acid, benzoylacetic acid, etc.), β-ketoesters (for example, lower alkyl esters suchas methyl, propyl, butyl esters and the like of the above-mentionedketonic acids), oxy-acids (for example, lactic acid, glycolic acid,α-oxy butyric acid, salicylic acid, etc.), lower alkyl esters of theabove-mentioned oxy-acids, oxy ketones (for example, diacetone alcohol,acetoin, etc.), diol, triol, higher carboxylic acid, alkanol amines (forexample, diethanolamine, triethanolamine, monoethanolamine), andpolyamine, in a proportion of 0.2 to 3 (in terms of number of stabilizermolecules)/(number of metal atoms).

In the present invention, the above-prepared organometallic compoundsolution is preferably subjected to filtration or the like to removeparticles, such that the number of particles having a particle diameterof 0.5 μm or more (particularly 0.3 μm or more, and more particularly0.2 μm or more) is 50 particles/mL or less per 1 mL of the solution.

Further, the number of particles in the corresponding organometalliccompound solution is measured using a light scattering particle counter.

If the number of particles having a particle diameter of 0.5 μm or morein the organometallic compound solution is higher than 50 particles/mL,the long-term storage stability is deteriorated. The smaller number ofparticles having a particle diameter of 0.5 μm or more in theorganometallic compound solution is preferable. Particularly preferredis 30 particles/mL or less.

Although there is no particular limitation to the method of treating anorganometallic compound solution to achieve the above-mentioned particlenumber after preparation thereof, for example, the following methods maybe employed. The first method is a filtration method of transferring asolution to a syringe, using a commercially available membrane filterhaving a pore diameter of 0.2 μm. The second method is a pressurefiltration method with combination of a commercially available membranefilter having a pore diameter of 0.05 μm and a pressurized tank. Thethird method is a cycle filtration with combination of the filter usedin the second method and a solution circulation bath.

In any one of the above methods, the particle capture rate of the filtervaries depending on the solution transfer pressure. It is generallyknown that lower pressure leads to a higher capture rate. In particular,with regard to the first and second methods, in order to achieve thecondition that the number of particles having a particle diameter of 0.5μm or more is 50 or less, the solution is preferably passed through afilter at a very low rate under a low pressure.

By using the composition for the formation of a ferroelectric thin filmin accordance with the present invention, it is possible to convenientlyform a ferroelectric thin film in the form of a mixed composite metaloxide formed of a mixture of a composite metal oxide A of one materialselected from the group consisting of PLZT, PZT, and PT with a compositeoxide B (composite metal oxide) including one or more selected from thegroup consisting of Sn, Sm, Nd and Y (yttrium).

In order to prepare a ferroelectric thin film using the composition forthe formation of a ferroelectric thin film in accordance with thepresent invention, the above composition is applied to a heat-resistantsubstrate by an application method such as spin coating, dip coating, orLiquid Source Misted Chemical Deposition (LSMCD), followed by drying(pre-baking) and main baking.

Specific examples of the heat-resistant substrate that can be usedherein include, but are not limited to, substrates whose substratesurface part employs a perovskite-type conductive oxide such assingle-crystalline Si, polycrystalline Si, Pt, Pt (uppermost layer)/Ti,Pt (uppermost layer)/Ta, Ru, RuO₂, Ru (uppermost layer)/RuO₂, RuO₂(uppermost layer)/Ru, Ir, IrO₂, Ir (uppermost layer)/IrO₂, Pt(uppermostlayer)/Ir, Pt (uppermost layer)/IrO₂, SrRuO₃ or (La_(x)Sr_((1−x)))CoO₃.

In addition, when a desired film thickness cannot be obtained by onetime of application, the application and drying processes are repeatedseveral times, and then main baking is carried out. As used herein, theterm “desired film thickness” refers to a thickness of the ferroelectricthin film which is obtained after the main baking. For use in a thinfilm capacitor with a high capacity density, a film thickness of theferroelectric thin film after the main baking is in the range of 50 to500 nm.

Further, since the pre-baking is carried out for the removal of thesolvent and for the conversion of an organometallic compound into acomposite oxide by pyrolysis or hydrolysis, the pre-baking is carriedout in air or under an oxidative atmosphere or water vapor-containingatmosphere. Also with regard to heating in air, moisture necessary forhydrolysis is sufficiently secured from moisture in air. The heating maybe carried out in two steps, i.e. low-temperature heating for theremoval of the solvent and high-temperature heating for thedecomposition of the organometallic compound.

The main baking is a process for baking to crystallize the thin filmobtained by the pre-baking at a temperature equal to or higher than itscrystallization temperature. Thereby, a ferroelectric thin film can beobtained. A baking atmosphere for this crystallization process ispreferably O₂, N₂, Ar, N₂O or H₂, or a mixed gas thereof.

When the composite oxide B contains Sn, the pre-baking is carried out ata temperature of 150 to 550° C. for 1 to 30 minutes, and the main bakingis carried out at a temperature of 450 to 800° C. for 1 to 10 minutes.The main baking may also be carried out by rapid thermal annealing (RTAtreatment). When the main baking is carried out by RTA treatment, thetemperature elevation rate is preferably in the range of 10 to 100°C./sec.

When the composite oxide B contains one or more selected from the groupconsisting of Sm, Nd and Y (yttrium), the pre-baking is carried out at atemperature of 150 to 550° C. for 5 to 10 minutes, and the main bakingis carried out at a temperature of 450 to 800° C. for 1 to 60 minutes.The main baking may also be carried out by rapid thermal annealing (RTAtreatment). When the main baking is carried out by RTA treatment, thetemperature elevation rate is preferably in the range of 10 to 100°C./sec.

The thus formed ferroelectric thin film of the present inventioncontaining one or more selected from the group consisting of Sn, Sm, Ndand Y (yttrium) has a significantly improved specific permittivity ascompared to a conventional ferroelectric thin film and is excellent inbasic characteristics as a capacitor, and is therefore preferable foruse in a thin film capacitor having a high capacity density. Further,the ferroelectric thin film of the present invention is also excellentin basic characteristics as IPD.

Further, the ferroelectric thin film in Group 2 of the present inventioncan be used as a constituent material for a composite electroniccomponent of a thin-film condenser, a capacitor, an IPD, a DRAM memorycondenser, a multilayer capacitor, a transistor gate insulator, anonvolatile memory, a pyroelectric infrared detection device, apiezoelectric device, an electro-optical device, an actuator, aresonator, an ultrasonic motor, or an LC noise filter device. Inparticular, the ferroelectric thin film of Group 2 can be used in thecomposite electronic component which corresponds to a frequency band of100 MHz or higher.

[Group 3]

The composition for the formation of a ferroelectric thin film in Group3 is a composition for the formation of a ferroelectric thin film of onematerial selected from the group consisting of PLZT, PZT, and PT. Aferroelectric thin film formed using this composition is in the form ofa mixed composite metal oxide formed of a mixture of a composite metaloxide A represented by the general formula (1):(Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In the formula (1), 0.9<x<1.3,0≦y<0.1, and 0≦z<0.9] with a carboxylic acid B which is represented bythe general formula (2): C_(n)H_(2n+1)COOH (wherein 3≦n≦7) and iscapable of taking the structure of the following general ChemicalFormula (3) upon coordination with the metal.

[In the Chemical Formula (3), within the range satisfying “n” of thegeneral formula (2): C_(n)H_(2n+1) COOH, R1, R2, R3, R4, R5, and R6represent hydrogen, a methyl group or an ethyl group, M represents Pb,La, Zr or Ti, and m represents a valence of M].

In addition, the film-forming material is PLZT when y≠0 and z≠0 in theformula (1), the film-forming material is PZT when y=0 and z≠0, and thefilm-forming material is PT when y=0 and z=0. The composition iscomposed of an organometallic compound solution wherein the raw materialconstituting the composite metal oxide A and the carboxylic acid B aredissolved in an organic solvent in such a manner that the molar ratioB/A of the carboxylic acid B to the composite metal oxide A is in therange of 0<B/A<0.2, preferably 0.001≦B/A≦0.1, more preferably0.03≦B/A≦0.1, and more particularly preferably 0.05≦B/A≦0.1.

Since the carboxylic acid B is mixed within the above-specified range,the carboxylic acid (pseudo-carboxylate) coordinated to the metalelement takes a structure of a 6-membered ring by the action of ahydrogen bond, which results in ideal decomposition of the carbon bondat a low temperature (for example, the specification of Japanese PatentApplication Laid-Open Publication No. Hei 9-52713, paragraph number[0023]; and Allen W. Apblett et al., Mat. Res. Soc. Symp. Proc. Vol. 271pp. 77, etc.), so low-temperature crystallization becomes possible, andcrystal growth is sufficiently carried out when baking. Thereby, it isbelieved that the specific permittivity is improved.

Further, it is believed that the presence of a 6-membered ring-formedcarboxylic acid coordinated to a sterically bulky metal element on thesubstrate interface inhibits the formation of crystal nuclei uponpre-baking and baking. For these reasons, a crystal nucleation densityis decreased, so crystal growth at the substrate interface ispredominant over the formation of crystal nuclei at the substrateinterface, thus achieving sufficient grain growth upon baking. Alsobased on this reason, it is believed that the specific permittivity isimproved.

Therefore, the ferroelectric thin film formed using the composition forthe formation of a ferroelectric thin film in accordance with thepresent invention can significantly improve the specific permittivity,as compared to a conventional ferroelectric thin film. In addition, ifthe molar ratio B/A of the carboxylic acid B to the composite metaloxide A is lower than the lower limit or higher than the upper limit,there is no significant difference as compared to no addition of thecarboxylic acid B, so it is not suitable for use in a thin filmcapacitor having a high capacity density.

The raw material for the composite metal oxide A is preferably acompound whose organic radical is bound to each metal element of Pb, La,Zr and Ti through oxygen or nitrogen atoms thereof. For example, the rawmaterial for the composite metal oxide is one or more selected from thegroup consisting of a metal alkoxide, a metal diol complex, a metaltriol complex, a metal carboxylate, a metal β-diketonato complex, ametal β-diketoester complex, a metal β-iminoketo complex, and a metalamino complex. The particularly preferred compound is a metal alkoxide,a partial hydrolysate thereof, or an organic acid salt thereof. Amongthem, examples of the Pb compound and the La compound include organicacid salts such as acetic acid salts (lead acetate, lanthanum acetate),and alkoxides such as lead diisopropoxide. Examples of the Ti compoundinclude alkoxides such as titanium tetraethoxide, titaniumtetraisopropoxide, titanium tetrabutoxide, and titanium dimethoxydiisopropoxide. Examples of the Zr compound preferably include alkoxidesas in the Ti compound. The metal alkoxide may be used without furtherprocessing, or may be used in the form of a partial hydrolysate thereoffor the purpose of facilitating the decomposition thereof.

Examples of the carboxylic acid B that can be used in the compositionfor the formation of a ferroelectric thin film in accordance with thepresent invention include compounds shown in Table 1 below.

TABLE 1 Number of n in C_(n)H_(2n+1)COOH Compound name n = 3 n-butyricacid (In the formula (3), R1 to R6 represent hydrogen) n = 4 α-methylbutyric acid (In the formula (3), R1 represents a methyl group, and R2to R6 represent hydrogen) iso-valeric acid (In the formula (3), R1, R2and R4 to R6 represent hydrogen, and R3 represents a methyl group) n = 52-ethyl butyric acid (In the formula (3), R1 represents an ethyl group,and R2 to R6 represent hydrogen) 2,2-dimethyl butyric acid (In theformula (3), R1 and R2 represent a methyl group, and R3 to R6 representhydrogen) 3,3-dimethyl butyric acid (In the formula (3), R3 and R4represent a methyl group, and R1, R2, R5 and R6 represent hydrogen)2,3-dimethyl butyric acid (In the formula (3), R1 and R3 representmethyl group, and R2 and R4 to R6 represent hydrogen) 3-methyl pentanoicacid (In the formula (3), R3 and R5 represent a methyl group, and R1,R2, R4 and R6 represent hydrogen) 4-methyl pentanoic acid (In theformula (3), R5 and R6 represent a methyl group, and R1 to R4 representhydrogen) n = 6 2-ethyl pentanoic acid (In the formula (3), R1represents an ethyl group, R5 represents a methyl group, and R2 to R4and R6 represent hydrogen) 3-ethyl pentanoic acid (In the formula (3),R3 represents an ethyl group, R5 represents a methyl group, and R1, R2,R4 and R6 represent hydrogen) 2,2-dimethyl pentanoic acid (In theformula (3), R1, R2 and R5 represent a methyl group, and R3, R4 and R6represent hydrogen) 3,3-dimethyl pentanoic acid (In the formula (3), R3,R4 and R5 represent a methyl group, and R1, R2 and R6 representhydrogen) 2,3-dimethyl pentanoic acid (In the formula (3), R1, R3 and R5represent a methyl group, and R2, R4 and R6 represent hydrogen) 4-methylhexanoic acid (In the formula (3), R5 represents a methyl group, R6represents an ethyl group, and R1 to R4 represent hydrogen) n = 72-ethyl hexanoic acid (In the formula (3), R1 and R5 represent an ethylgroup, and R2 to R4 and R6 represent hydrogen) 3-ethyl hexanoic acid (Inthe formula (3), R3 and R5 represent an ethyl group, and R1, R2, R4 andR6 represent hydrogen) 2,2-dimethyl hexanoic acid (In the formula (3),R1 and R2 represent a methyl group, R5 represent an ethyl group, and R3,R4 and R6 represent hydrogen) 3,3-dimethyl hexanoic acid (In the formula(3), R3 and R4 represent a methyl group, R5 represents an ethyl group,and R1, R2 and R6 represent hydrogen)

In order to prepare the composition for the formation of a ferroelectricthin film in accordance with the present invention, these raw materialsare dissolved in a suitable solvent at the ratio corresponding to adesired ferroelectric thin film composition, thereby preparing asolution at a concentration suitable for application.

Although the solvent for a composition for the formation of aferroelectric thin film used herein is appropriately determineddepending on the type of the raw materials to be used, there may begenerally used alcohol, ester, ketones (for example, acetone, methylethyl ketone), ethers (for example, dimethyl ether, diethyl ether),cycloalkanes (for example, cyclohexane, cyclohexanol), aromatics (forexample, benzene, toluene, xylene), tetrahydrofuran, or a mixed solventof two or more thereof.

As the ester, it is preferred to use ethyl acetate, propyl acetate,n-butyl acetate, sec-butyl acetate, tert-butyl acetate, isobutylacetate, n-amyl acetate, sec-amyl acetate, tert-amyl acetate, or isoamylacetate. As the alcohol, it is preferred to use 1-propanol, 2-propanol,1-butanol, 2-butanol, iso-butyl alcohol, 1-pentanol, 2-pentanol,2-methyl-2-pentanol, or 2-methoxy ethanol.

In addition, the total concentration of an organometallic compound in anorganometallic compound solution of the composition for the formation ofa ferroelectric thin film is preferably in the range of 0.1 to 20% bymass, in terms of the metal oxides.

The organometallic compound solution may contain, if necessary, astabilizer selected from the group consisting of β-diketones (forexample, acetylacetone, heptafluorobutanoyl pyvaloyl methane, dipyvaloylmethane, trifluoro acetylacetone, benzoyl acetone, etc.), β-ketonicacids (for example, acetoacetic acid, propionyl acetic acid, benzoylacetic acid, etc.), β-ketoesters (for example, lower alkyl esters suchas methyl, propyl, butyl esters and the like of the above-mentionedketonic acids), oxy-acids (for example, lactic acid, glycolic acid,α-oxy butyric acid, salicylic acid, etc.), lower alkyl esters of theabove-mentioned oxy-acids, oxy ketones (for example, diacetone alcohol,acetoin, etc.), diol, triol, alkanol amines (for example,diethanolamine, triethanolamine, monoethanolamine), and polyamine, in aproportion of 0.2 to 3 (in terms of (number of stabilizermolecules)/(number of metal atoms)).

In the present invention, the above-prepared organometallic compoundsolution is preferably subjected to filtration or the like to removeparticles, such that the number of particles having a particle diameterof 0.5 μm or more (particularly 0.3 μm or more, and more particularly0.2 μm or more) is 50 particles/mL or less per 1 mL of the solution.

If the number of particles having a particle diameter of 0.5 μm or morein the organometallic compound solution is higher than 50 particles/mL,the long-term storage stability is deteriorated. The smaller number ofparticles having a particle diameter of 0.5 μm or more in theorganometallic compound solution is preferable. Particularly preferredis 30 particles/mL or less.

Although there is no particular limitation to the method of treating anorganometallic compound solution to achieve the above-mentioned particlenumber after preparation thereof, for example, the following methods maybe employed. The first method is a filtration method of transferring asolution to a syringe, using a commercially available membrane filterhaving a pore diameter of 0.2 μm. The second method is a pressurefiltration method with combination of a commercially available membranefilter having a pore diameter of 0.05 μm and a pressurized tank. Thethird method is a cycle filtration with combination of the filter usedin the second method and a solution circulation bath.

In any one of the above methods, the particle capture rate of the filtervaries depending on the solution transfer pressure. It is generallyknown that lower pressure leads to a higher capture rate. In particular,with regard to the first and second methods, in order to achieve thecondition that the number of particles having a particle diameter of 0.5μm or more is 50 or less, the solution is preferably passed through afilter at a very low rate under a low pressure.

By using the composition for the formation of a ferroelectric thin filmin accordance with the present invention, it is possible to convenientlyform a ferroelectric thin film in the form of a composite metal oxide Aof one material selected from the group consisting of PLZT, PZT, and PT.

In order to prepare a ferroelectric thin film using the composition forthe formation of a ferroelectric thin film in accordance with thepresent invention, the above composition is applied to a heat-resistantsubstrate by an application method such as spin coating, dip coating, orLiquid Source Misted Chemical Deposition (LSMCD), followed by drying(pre-baking) and main baking.

Specific examples of the heat-resistant substrate that can be usedherein include, but are not limited to, substrates whose substratesurface part employs a perovskite-type conductive oxide such assingle-crystalline Si, polycrystalline Si, Pt, Pt (uppermost layer)/Ti,Pt (uppermost layer)/Ta, Ru, RuO₂, Ru (uppermost layer)/RuO₂, RuO₂(uppermost layer)/Ru, Ir, IrO₂, Ir (uppermost layer)/IrO₂, Pt(uppermostlayer)/Ir, Pt (uppermost layer)/IrO₂, SrRuO₃ or (La_(x)Sr_((1−x))) CoO₃.

In addition, when a desired film thickness cannot be obtained by onetime of application, the application and drying processes are repeatedseveral times, and then main baking is carried out. As used herein, theterm “desired film thickness” refers to a thickness of the ferroelectricthin film which is obtained after the main baking. For use in a thinfilm capacitor with a high capacity density, a film thickness of theferroelectric thin film after the main baking is in the range of 50 to500 nm.

Further, since the pre-baking is carried out for the removal of thesolvent and for the conversion of an organometallic compound into acomposite oxide by pyrolysis or hydrolysis, the pre-baking is carriedout in air or under an oxidative atmosphere or water vapor-containingatmosphere. Also with regard to heating in air, moisture necessary forhydrolysis is sufficiently secured from moisture in air. The heating maybe carried out in two steps, i.e. low-temperature heating for theremoval of the solvent and high-temperature heating for thedecomposition of the organometallic compound.

The main baking is a process for baking to crystallize the thin filmobtained by the pre-baking at a high temperature equal to or higher thanits crystallization temperature. Thereby, a ferroelectric thin film canbe obtained. A baking atmosphere for this crystallization process ispreferably O₂, N₂, Ar, N₂O or H₂, or a mixed gas thereof.

The pre-baking is carried out at a temperature of 150 to 550° C. for 5to 10 minutes, and the main baking is carried out at a temperature of450 to 800° C. for 1 to 60 minutes. The main baking may also be carriedout by rapid thermal annealing (RTA treatment). When the main baking iscarried out by RTA treatment, the temperature elevation rate ispreferably in the range of 10 to 100° C./sec.

The thus formed ferroelectric thin film of Group 3 has a significantlyimproved specific permittivity as compared to a conventionalferroelectric thin film and is excellent in basic characteristics as acapacitor, and is therefore preferable for use in a thin film capacitorhaving a high capacity density. Further, the ferroelectric thin film ofthe present invention also has excellent in basic characteristics asIPD.

Further, the ferroelectric thin film of Group 3 can be used as aconstituent material for a composite electronic component of a thin-filmcondenser, a capacitor, an IPD, a DRAM memory condenser, a multilayercapacitor, a transistor gate insulator, a nonvolatile memory, apyroelectric infrared detection device, a piezoelectric device, anelectro-optical device, an actuator, a resonator, an ultrasonic motor,or an LC noise filter device. In particular, the ferroelectric thin filmof Group 3 can be used in the composite electronic component whichcorresponds to a frequency band of 100 MHz or higher.

EXAMPLES

[Group 1]

Hereinafter, Examples A-1 to A-29 of the present invention inconjunction with Comparative Examples A-1 to A-8 will be described inmore detail.

The following Examples A-1 to A-29 and Comparative Examples A-1 to A-8were carried out using the raw materials below.

Pb compound: lead acetate trihydrate

La compound: lanthanum acetate 1.5 hydrate

Zr compound: zirconium tetra-t-butoxide

Ti compound: titanium tetraisopropoxide

P (phosphorus) compound: P (phosphorus) triisopropoxide, triethylphosphate

Examples A-1 to A-29 and Comparative Examples A-1 to A-8

An organometallic compound (Pb, La compound, etc.) in the form of anorganic acid salt was dissolved in sufficiently dehydrated 2-methoxyethanol as an organic solvent, and water of crystallization was removedby azeotropic distillation. Then, an organometallic compound or organiccompound (Zr, Ti, P (phosphorus) compound, etc.) in the form of analkoxide was added and dissolved in the resulting solution. For thepurpose of solution stabilization, a 2-fold mol of acetylacetone ordiethanolamine was added relative to the alkoxide. Each element wasadded to PZT according to the addition element species and additiveamount as given in Table 2 or 3 below, thereby preparing a solution forthe formation of a thin film such that the total concentration oforganometallic compounds in terms of the metal oxides was about 10% byweight.

Using each solution, a thin film was formed by a CSD method, accordingto the following procedure.

That is, each solution was applied by a spin coating method at 500 rpmfor 3 seconds and then at 3000 rpm for 15 seconds to a 6 inch siliconsubstrate where a Pt thin film was sputtered on the surface thereof.

Then, pre-baking was carried out by heating the substrate on a hot plateat 350° C. for 10 minutes. After the application and pre-bakingprocesses were repeated 6 times, the substrate was subjected to bakingin a rapid thermal annealer (RTA) under a 100% oxygen atmosphere or dryair atmosphere at 700° C. for 1 minute, thereby forming a ferroelectricthin film having a film thickness of 300 nm.

Next, a Pt upper electrode of about 250 μm□ was fabricated on thesurface of the substrate by a sputtering method using a metal mask, a DCvoltage was applied between Pt lower electrodes immediately under theferroelectric thin film, and I-V characteristics (voltage dependence ofleakage current density and dielectric strength voltage) were evaluated.The measurement of I-V characteristics was carried out using a 236 SMU(manufactured by Keithley) under the conditions of Bias step 0.5 V, adelay time of 0.1 sec, a temperature of 23° C., and a hygrometry of50±0%. The term “dielectric strength voltage” is defined as a voltage atthe (n−1)th Bias step where the leakage current density exceeds 1 A/cm².The results are given in Tables 2 and 3 below and FIGS. 1 to 4.

TABLE 2 Dielectric Addition element Added P strength species/Additive(Phosphorus) Added Baking Leakage current density (A/cm²) voltage amount(mol %) compound form stabilizer atmosphere at 5 V at 20 V at 50 V (V)Example A-1 P(III) 1% P(phosphorus) Acetylacetone Oxygen 2.31 × 10⁻⁷3.89 × 10⁻⁷ 2.15 × 10⁻⁶ 81.5 triisopropoxide Example A-2 P(III) 3%P(phosphorus) Acetylacetone Oxygen 1.67 × 10⁻⁷ 2.22 × 10⁻⁷ 7.99 × 10⁻⁷72 triisopropoxide Example A-3 P(V) 1% Triethyl phosphate AcetylacetoneOxygen 6.96 × 10⁻⁷ 6.03 × 10⁻⁶ 6.49 × 10⁻⁵ 74 Example A-4 P(V) 3%Triethyl phosphate Acetylacetone Oxygen 3.17 × 10⁻⁷ 7.84 × 10⁻⁷ 4.79 ×10⁻⁶ 86 Example A-5 P(V) 5% Triethyl phosphate Acetylacetone Oxygen 2.57× 10⁻⁷ 4.99 × 10⁻⁷ 2.84 × 10⁻⁶ 84.5 Example A-6 P(III) 1%, Sn 1%P(phosphorus) Acetylacetone Oxygen 1.41 × 10⁻⁷ 1.10 × 10⁻⁶ — 25.5triisopropoxide Example A-7 P(V) 1%, Sn 1% Triethyl phosphateAcetylacetone Oxygen 3.80 × 10⁻⁶ — — 19.5 Example A-8 P(V) 5%, Sn 1%Triethyl phosphate Acetylacetone Oxygen 1.81 × 10⁻⁷ 1.76 × 10⁻⁶ — 27Example A-9 P(III) 1%, Si 0.5% P(phosphorus) Acetylacetone Oxygen 2.05 ×10⁻⁷ 3.11 × 10⁻⁷ 7.73 × 10⁻⁷ 83.5 triisopropoxide Example A-10 P(V) 1%,Si 0.5% Triethyl phosphate Acetylacetone Oxygen 4.31 × 10⁻⁷ 1.02 × 10⁻⁶6.84 × 10⁻⁶ 83.5 Example A-11 P(V) 1%, La 1% Triethyl phosphateAcetylacetone Oxygen 1.22 × 10⁻⁷ 7.34 × 10⁻⁷ 6.59 × 10⁻⁶ 82 Example A-12P(V) 3%, La 1% Triethyl phosphate Acetylacetone Oxygen 1.41 × 10⁻⁷ 5.43× 10⁻⁷ 4.15 × 10⁻⁶ 81.5 Example A-13 P(V) 3%, La 3% Triethyl phosphateAcetylacetone Oxygen 7.49 × 10⁻⁸ 1.78 × 10⁻⁷ 1.57 × 10⁻⁶ 82 ComparativeNon dope — Acetylacetone Oxygen 8.08 × 10⁻⁷ 1.00 × 10⁻⁵ 2.06 × 10⁻⁴ 70Example A-1 PZT (110/52/48) Comparative La 3% — Acetylacetone Oxygen9.57 × 10⁻⁸ 4.73 × 10⁻⁷ 6.43 × 10⁻⁶ 73.5 Example A-2 Comparative La 1% —Acetylacetone Oxygen 1.99 × 10⁻⁷ 8.91 × 10⁻⁷ 1.11 × 10⁻⁵ 61.5 ExampleA-3 Comparative Sn 1% — Acetylacetone Oxygen 8.66 × 10⁻⁶ — — 16 ExampleA-4

TABLE 3 Dielectric Addition element Added P Leakage current strengthspecies/Additive (phosphorus) Added Baking density (A/cm²) voltageamount (mol %) compound form stabilizer atmosphere at 20 V (V) ExampleA-14 P(III) 0.3% P(phosphorus) Acetylacetone Dry air 9.23 × 10⁻⁶ 70triisopropoxide Example A-15 P(III) 1% P(phosphorus) Acetylacetone Dryair 6.23 × 10⁻⁷ 72 triisopropoxide Example A-16 P(III) 3% P(phosphorus)Acetylacetone Dry air 3.45 × 10⁻⁷ 75 triisopropoxide Example A-17 P(III)5% P(phosphorus) Acetylacetone Dry air 2.14 × 10⁻⁷ 75 triisopropoxideExample A-18 P(III) 10% P(phosphorus) Acetylacetone Dry air 2.34 × 10⁻⁷84 triisopropoxide Example A-19 P(III) 20% P(phosphorus) AcetylacetoneDry air 3.43 × 10⁻⁷ 83 triisopropoxide Example A-20 P(V) 0.3% Triethylphosphate Diethanolamine Oxygen 8.55 × 10⁻⁶ 71 Example A-21 P(V) 1%Triethyl phosphate Diethanolamine Oxygen 6.23 × 10⁻⁶ 71 Example A-22P(V) 3% Triethyl phosphate Diethanolamine Oxygen 3.76 × 10⁻⁶ 75 ExampleA-23 P(V) 5% Triethyl phosphate Diethanolamine Oxygen 1.12 × 10⁻⁶ 78Example A-24 P(V) 10% Triethyl phosphate Diethanolamine Oxygen 9.34 ×10⁻⁷ 80 Example A-25 P(V) 20% Triethyl phosphate Diethanolamine Oxygen1.23 × 10⁻⁶ 81 Example A-26 P(V) 1%, La 1% Triethyl phosphateAcetylacetone Dry air 8.92 × 10⁻⁷ 80 Example A-27 P(V) 3%, La 3%Triethyl phosphate Acetylacetone Dry air 8.23 × 10⁻⁷ 82 Example A-28P(V) 3%, La 1% Triethyl phosphate Acetylacetone Dry air 7.23 × 10⁻⁷ 78Example A-29 P(V) 3%, La 3% Triethyl phosphate Acetylacetone Dry air2.44 × 10⁻⁷ 80 Comparative Non dope — Acetylacetone Dry air 1.35 × 10⁻⁶65 Example A-5 PZT (110/52/48) Comparative Non dope — DiethanolamineOxygen 1.26 × 10⁻⁶ 63 Example A-6 PZT (110/52/48) Comparative La 1% —Acetylacetone Dry air 9.23 × 10⁻⁷ 65 Example A-7 Comparative La 3% —Acetylacetone Dry air 5.24 × 10⁻⁷ 71 Example A-8

As can be seen from Table 2 and FIGS. 1 to 4, the ferroelectric thinfilms of Examples A-1 to A-5 with an addition of P (phosphorus)exhibited a decrease in leakage current density and simultaneously animprovement in dielectric strength voltage, as compared to theferroelectric thin film of Comparative Example A-1 with no addition of P(phosphorus).

Further, the same tendency was also observed from the comparison betweenthe ferroelectric thin films of Comparative Examples A-2 and A-3 with anaddition of La and the ferroelectric thin films of Examples A-11 to A-13with co-addition of P (phosphorus) and La.

As can be seen from Comparative Examples A-1 and A-4, the addition of Snresults in an increase in leakage current density, but as shown inExamples A-6 to A-8, coexistence of Sn with P (phosphorus) alsoexhibited a decrease in leakage current density and simultaneously animprovement in dielectric strength voltage.

In addition, as can be seen from the results of the ferroelectric thinfilms of Examples A-6 to A-10, coexistence of P (phosphorus) withanother ingredient (such as Sn or Si) in an amount of about 1% alsoexhibited favorable effects of P (phosphorus), and P (phosphorus) wasfound as an addition element which exerts effects in a very uniquefashion.

Further, as can be seen from the results of the ferroelectric thin filmsof Examples A-14 to A-19, Examples A-20 to A-25, and ComparativeExamples A-5 and A-6, a reduced leakage current density and an improveddielectric strength voltage could be simultaneously achievedirrespective of the added P (phosphorus) compound form, stabilizer type,and baking atmosphere.

Further, as can be seen from the results of the ferroelectric thin filmsof Examples A-26 to A-29 and Comparative Examples A-7 and A-8, asatisfactory tendency was also observed even under the coexistence ofLa.

From these results, the ferroelectric thin films of Examples A-1 to A-29are excellent in leakage strength voltage and dielectric strengthvoltage and can realize a film thickness reduction, thus achieving ahigh capacity density.

The ferroelectric thin films prepared in Examples A-1 to A-29 exhibitexcellent basic characteristics as a capacitor, and can be used for athin film capacitor with a high capacity density.

Hereinafter, Examples B-1 to B-75 of the present invention inconjunction with Comparative Examples B-1 to B-6 will be described inmore detail.

Examples B-1 to B-5

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various silicon compounds (silicon 2-ethylhexanoate, silicon 2-ethyl butyrate, silicon tetraethoxide, silicontetra-n-butoxide, tetrakis(acetylacetonate) silicon) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples B-6 to B-10

Ferroelectric thin films were formed on substrates in the same manner asin Examples B-1 to B-5, except that 1.0 mol % (in outer percent) ofvarious silicon compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples B-11 to B-15

Ferroelectric thin films were formed on substrates in the same manner asin Examples B-1 to B-5, except that 3.0 mol % (in outer percent) ofvarious silicon compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples B-16 to B-20

Ferroelectric thin films were formed on substrates in the same manner asin Examples B-1 to B-5, except that 5.0 mol % (in outer percent) ofvarious silicon compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples B-21 to B-25

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate, lanthanum acetate 1.5 hydrate and propylene glycol (solvent)were added thereto, followed by reflux under a nitrogen atmosphere at atemperature of 150° C. Then, by-products were removed by distillationunder reduced pressure at 150° C., and propylene glycol was addedthereto, followed by concentration adjustment to obtain a liquidcontaining a 30% by mass concentration of a metal compound in terms ofoxides. Thereafter, dilute alcohol was added to obtain a sol-gel liquidcontaining a 10% by mass concentration of a metal compound with a metalratio of Pb/La/Zr/Ti=110/3/52/48 in terms of oxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various silicon compounds (silicon 2-ethylhexanoate, silicon 2-ethyl butyrate, silicon tetraethoxide, silicontetra-n-butoxide, tetrakis(acetylacetonate) silicon) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Comparative Example B-1

A ferroelectric thin film was formed on a substrate in the same manneras in Examples B-1 to B-5, except that a thin film-forming solution wasprepared with no addition of silicon compounds to the sol-gel liquid.

Comparative Example B-2

A ferroelectric thin film was formed on a substrate in the same manneras in Examples B-21 to B-25, except that a thin film-forming solutionwas prepared with no addition of silicon compounds to the sol-gelliquid.

Examples B-26 to B-30

First, zirconium tetra-n-butoxide and diethanolamine (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide anddiethanolamine (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various silicon compounds (silicon 2-ethylhexanoate, silicon 2-ethyl butyrate, silicon tetraethoxide, silicontetra-n-butoxide, tetrakis(acetylacetonate) silicon) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples B-31 to B-35

Ferroelectric thin films were formed on substrates in the same manner asin Examples B-26 to B-30, except that 1.0 mol % (in outer percent) ofvarious silicon compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples B-36 to B-40

Ferroelectric thin films were formed on substrates in the same manner asin Examples B-26 to B-30, except that 3.0 mol % (in outer percent) ofvarious silicon compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples B-41 to B-45

Ferroelectric thin films were formed on substrates in the same manner asin Examples B-26 to B-30, except that 5.0 mol % (in outer percent) ofvarious silicon compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples B-46 to B-50

First, zirconium tetra-n-butoxide and diethanolamine (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide anddiethanolamine (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate, lanthanum acetate 1.5 hydrate and propylene glycol (solvent)were added thereto, followed by reflux under a nitrogen atmosphere at atemperature of 150° C. Then, by-products were removed by distillationunder reduced pressure at 150° C., and propylene glycol was addedthereto, followed by concentration adjustment to obtain a liquidcontaining a 30% by mass concentration of a metal compound in terms ofoxides. Thereafter, dilute alcohol was added to obtain a sol-gel liquidcontaining a 10% by mass concentration of a metal compound with a metalratio of Pb/La/Zr/Ti=110/3/52/48 in terms of oxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various silicon compounds (silicon 2-ethylhexanoate, silicon 2-ethyl butyrate, silicon tetraethoxide, silicontetra-n-butoxide, tetrakis(acetylacetonate) silicon) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Comparative Example B-3

A ferroelectric thin film was formed on a substrate in the same manneras in Examples B-26 to B-30, except that a thin film-forming solutionwas prepared with no addition of silicon compounds to the sol-gelliquid.

Comparative Example B-4

A ferroelectric thin film was formed on a substrate in the same manneras in Examples B-46 to B-50, except that a thin film-forming solutionwas prepared with no addition of silicon compounds to the sol-gelliquid.

Examples B-51 to B-55

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various silicon compounds (silicon 2-ethylhexanoate, silicon 2-ethyl butyrate, silicon tetraethoxide, silicontetra-n-butoxide, tetrakis(acetylacetonate) silicon) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a dry air atmosphere at 700° C. for 1 minute, thereby forming aferroelectric thin film having a film thickness of 270 nm.

Examples B-56 to B-60

Ferroelectric thin films were formed on substrates in the same manner asin Examples B-51 to B-55, except that 1.0 mol % (in outer percent) ofvarious silicon compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples B-61 to B-65

Ferroelectric thin films were formed on substrates in the same manner asin Examples B-51 to B-55, except that 3.0 mol % (in outer percent) ofvarious silicon compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples B-66 to B-70

Ferroelectric thin films were formed on substrates in the same manner asin Examples B-51 to B-55, except that 5.0 mol % (in outer percent) ofvarious silicon compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples B-71 to B-75

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate, lanthanum acetate 1.5 hydrate and propylene glycol (solvent)were added thereto, followed by reflux under a nitrogen atmosphere at atemperature of 150° C. Then, by-products were removed by distillationunder reduced pressure at 150° C., and propylene glycol was addedthereto, followed by concentration adjustment to obtain a liquidcontaining a 30% by mass concentration of a metal compound in terms ofoxides. Thereafter, dilute alcohol was added to obtain a sol-gel liquidcontaining a 10% by mass concentration of a metal compound with a metalratio of Pb/La/Zr/Ti=110/3/52/48 in terms of oxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various silicon compounds (silicon 2-ethylhexanoate, silicon 2-ethyl butyrate, silicon tetraethoxide, silicontetra-n-butoxide, tetrakis(acetylacetonate) silicon) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a dry air atmosphere at 700° C. for 1 minute, thereby forming aferroelectric thin film having a film thickness of 270 nm.

Comparative Example B-5

A ferroelectric thin film was formed on a substrate in the same manneras in Examples B-51 to B-55, except that a thin film-forming solutionwas prepared with no addition of silicon compounds to the sol-gelliquid.

Comparative Example B-6

A ferroelectric thin film was formed on a substrate in the same manneras in Examples B-71 to B-75, except that a thin film-forming solutionwas prepared with no addition of silicon compounds to the sol-gelliquid.

Comparative Evaluation

For a substrate on which each of the ferroelectric thin films preparedin Examples B-1 to B-75 and Comparative Examples B-1 to B-6 was formed,a Pt upper electrode of about 250 μm□ was fabricated on the surface ofthe substrate by a sputtering method using a metal mask, a DC voltagewas applied between Pt lower electrodes immediately under theferroelectric thin film, and I-V characteristics (voltage dependence ofleakage current density and dielectric strength voltage) were evaluated.The results obtained are given in Tables 4 to 6 below, respectively. Inaddition, I-V characteristic diagrams of Examples B-3, B-8, B-13, B-18and B-23, and Comparative Examples B-1 and B-2 are given in FIGS. 5 to11, respectively. The measurement of I-V characteristics was carried outusing a 236 SMU (manufactured by Keithley) under the conditions of abias step of 0.5 V, a delay time of 0.1 sec, a temperature of 23° C.,and a hygrometry of 50±0%. The term “dielectric strength voltage” isdefined as a voltage at the (n−1)th bias step where the leakage currentdensity exceeds 1 A/cm². In addition, “>99.5” in Tables 4 to 6represents a voltage measurement limit of a measuring device.

TABLE 4 Dielectric Addition element Added P strength species/Additive(Phosphorus) Added Baking Leakage current density (A/cm²) voltage amount(mol %) compound form stabilizer atmosphere at 5 V at 20 V at 50 V (V)Example B-1 PZT + Si 0.5% 2-ethyl hexanoate Acetylacetone Oxygen 6.12 ×10⁻⁷ 3.10 × 10⁻⁶ 2.01 × 10⁻⁵ 77.0 Example B-2 PZT + Si 0.5% 2-ethylbutyrate Acetylacetone Oxygen 5.84 × 10⁻⁷ 2.86 × 10⁻⁶ 1.86 × 10⁻⁵ 80.0Example B-3 PZT + Si 0.5% Ethoxide Acetylacetone Oxygen 5.77 × 10⁻⁷ 2.99× 10⁻⁶ 1.97 × 10⁻⁵ 78.0 Example B-4 PZT + Si 0.5% n-butoxideAcetylacetone Oxygen 5.97 × 10⁻⁷ 2.94 × 10⁻⁶ 2.05 × 10⁻⁵ 79.5 ExampleB-5 PZT + Si 0.5% Acetylacetonate Acetylacetone Oxygen 6.01 × 10⁻⁷ 2.79× 10⁻⁶ 1.96 × 10⁻⁵ 78.0 Example B-6 PZT + Si 1% 2-ethyl hexanoateAcetylacetone Oxygen 3.53 × 10⁻⁷ 6.25 × 10⁻⁷ 3.32 × 10⁻⁶ 88.0 ExampleB-7 PZT + Si 1% 2-ethyl butyrate Acetylacetone Oxygen 4.01 × 10⁻⁷ 6.63 ×10⁻⁷ 3.36 × 10⁻⁶ 89.0 Example B-8 PZT + Si 1% Ethoxide AcetylacetoneOxygen 3.74 × 10⁻⁷ 6.50 × 10⁻⁷ 3.43 × 10⁻⁶ 87.5 Example B-9 PZT + Si 1%n-butoxide Acetylacetone Oxygen 3.82 × 10⁻⁷ 6.33 × 10⁻⁷ 3.46 × 10⁻⁶ 86.5Example B-10 PZT + Si 1% Acetylacetonate Acetylacetone Oxygen 3.69 ×10⁻⁷ 6.84 × 10⁻⁷ 3.51 × 10⁻⁵ 86.5 Example B-11 PZT + Si 3% 2-ethylhexanoate Acetylacetone Oxygen 2.33 × 10⁻⁷ 4.31 × 10⁻⁷ 1.35 × 10⁻⁶ 94.0Example B-12 PZT + Si 3% 2-ethyl butyrate Acetylacetone Oxygen 2.62 ×10⁻⁷ 4.03 × 10⁻⁷ 1.40 × 10⁻⁶ 97.5 Example B-13 PZT + Si 3% EthoxideAcetylacetone Oxygen 2.49 × 10⁻⁷ 4.16 × 10⁻⁷ 1.31 × 10⁻⁶ 95.0 ExampleB-14 PZT + Si 3% n-butoxide Acetylacetone Oxygen 2.47 × 10⁻⁷ 4.18 × 10⁻⁷1.50 × 10⁻⁶ 95.5 Example B-15 PZT + Si 3% Acetylacetonate AcetylacetoneOxygen 2.41 × 10⁻⁷ 4.08 × 10⁻⁷ 1.46 × 10⁻⁶ 95.0 Example B-16 PZT + Si 5%2-ethyl hexanoate Acetylacetone Oxygen 2.46 × 10⁻⁷ 2.84 × 10⁻⁷ 7.32 ×10⁻⁷ >99.5 Example B-17 PZT + Si 5% 2-ethyl butyrate AcetylacetoneOxygen 2.61 × 10⁻⁷ 2.74 × 10⁻⁷ 7.15 × 10⁻⁷ >99.5 Example B-18 PZT + Si5% Ethoxide Acetylacetone Oxygen 2.52 × 10⁻⁷ 2.79 × 10⁻⁷ 7.22 ×10⁻⁷ >99.5 Example B-19 PZT + Si 5% n-butoxide Acetylacetone Oxygen 2.42× 10⁻⁷ 2.75 × 10⁻⁷ 7.32 × 10⁻⁷ >99.5 Example B-20 PZT + Si 5%Acetylacetonate Acetylacetone Oxygen 2.51 × 10⁻⁷ 2.86 × 10⁻⁷ 7.31 ×10⁻⁷ >99.5 Example B-21 PLZT + Si 0.5% 2-ethyl hexanoate AcetylacetoneOxygen 7.21 × 10⁻⁸ 2.05 × 10⁻⁷ 1.25 × 10⁻⁶ 84.0 Example B-22 PLZT + Si0.5% 2-ethyl butyrate Acetylacetone Oxygen 7.47 × 10⁻⁸ 2.28 × 10⁻⁷ 1.30× 10⁻⁶ 85.5 Example B-23 PLZT + Si 0.5% Ethoxide Acetylacetone Oxygen7.34 × 10⁻⁸ 2.15 × 10⁻⁷ 1.20 × 10⁻⁶ 83.5 Example B-24 PLZT + Si 0.5%n-butoxide Acetylacetone Oxygen 7.38 × 10⁻⁸ 2.20 × 10⁻⁷ 1.25 × 10⁻⁶ 84.0Example B-25 PLZT + Si 0.5% Acetylacetonate Acetylacetone Oxygen 7.29 ×10⁻⁸ 2.19 × 10⁻⁷ 1.14 × 10⁻⁶ 84.0 Comparative Non dope — AcetylacetoneOxygen 8.08 × 10⁻⁷ 1.00 × 10⁻⁶ 2.06 × 10⁻⁴ 70.0 Example B-1 PZT(110/52/48) Comparative Non dope — Acetylacetone Oxygen 9.57 × 10⁻⁸ 4.73× 10⁻⁷ 6.43 × 10⁻⁶ 73.5 Example B-2 PLZT (110/3/52/48)

TABLE 5 Dielectric Addition element Added P strength species/Additive(Phosphorus) Added Baking Leakage current density (A/cm²) voltage amount(mol %) compound form stabilizer atmosphere at 5 V at 20 V at 50 V (V)Example B-26 PZT + Si 0.5% 2-ethyl hexanoate Diethanolamine Oxygen 6.03× 10⁻⁷ 2.99 × 10⁻⁶ 1.98 × 10⁻⁶ 78.5 Example B-27 PZT + Si 0.5% 2-ethylbutyrate Diethanolamine Oxygen 5.73 × 10⁻⁷ 2.95 × 10⁻⁶ 1.95 × 10⁻⁵ 79.5Example B-28 PZT + Si 0.5% Ethoxide Diethanolamine Oxygen 5.93 × 10⁻⁷3.05 × 10⁻⁶ 2.00 × 10⁻⁵ 79.5 Example B-29 PZT + Si 0.5% n-butoxideDiethanolamine Oxygen 5.72 × 10⁻⁷ 2.85 × 10⁻⁶ 1.90 × 10⁻⁵ 80.0 ExampleB-30 PZT + Si 0.5% Acetylacetonate Diethanolamine Oxygen 5.83 × 10⁻⁷2.88 × 10⁻⁶ 2.03 × 10⁻⁵ 80.0 Example B-31 PZT + Si 1% 2-ethyl hexanoateDiethanolamine Oxygen 3.93 × 10⁻⁷ 6.60 × 10⁻⁷ 3.61 × 10⁻⁶ 88.0 ExampleB-32 PZT + Si 1% 2-ethyl butyrate Diethanolamine Oxygen 3.62 × 10⁻⁷ 6.71× 10⁻⁷ 3.41 × 10⁻⁶ 87.5 Example B-33 PZT + Si 1% Ethoxide DiethanolamineOxygen 3.71 × 10⁻⁷ 6.55 × 10⁻⁷ 3.48 × 10⁻⁶ 87.0 Example B-34 PZT + Si 1%n-butoxide Diethanolamine Oxygen 3.91 × 10⁻⁷ 6.61 × 10⁻⁷ 3.50 × 10⁻⁶88.0 Example B-35 PZT + Si 1% Acetylacetonate Diethanolamine Oxygen 3.83× 10⁻⁷ 6.39 × 10⁻⁷ 3.35 × 10⁻⁶ 88.5 Example B-36 PZT + Si 3% 2-ethylhexanoate Diethanolamine Oxygen 2.41 × 10⁻⁷ 4.25 × 10⁻⁷ 1.31 × 10⁻⁶ 96.5Example B-37 PZT + Si 3% 2-ethyl butyrate Diethanolamine Oxygen 2.63 ×10⁻⁷ 4.35 × 10⁻⁷ 1.28 × 10⁻⁶ 96.0 Example B-38 PZT + Si 3% EthoxideDiethanolamine Oxygen 2.48 × 10⁻⁷ 4.12 × 10⁻⁷ 1.35 × 10⁻⁶ 96.0 ExampleB-39 PZT + Si 3% n-butoxide Diethanolamine Oxygen 2.61 × 10⁻⁷ 4.23 ×10⁻⁷ 1.41 × 10⁻⁶ 95.5 Example B-40 PZT + Si 3% AcetylacetonateDiethanolamine Oxygen 2.35 × 10⁻⁷ 4.08 × 10⁻⁷ 1.25 × 10⁻⁶ 97.0 ExampleB-41 PZT + Si 5% 2-ethyl hexanoate Diethanolamine Oxygen 2.41 × 10⁻⁷2.65 × 10⁻⁷ 7.31 × 10⁻⁷ >99.5 Example B-42 PZT + Si 5% 2-ethyl butyrateDiethanolamine Oxygen 2.48 × 10⁻⁷ 2.75 × 10⁻⁷ 7.22 × 10⁻⁷ >99.5 ExampleB-43 PZT + Si 5% Ethoxide Diethanolamine Oxygen 2.37 × 10⁻⁷ 2.77 × 10⁻⁷7.20 × 10⁻⁷ >99.5 Example B-44 PZT + Si 5% n-butoxide DiethanolamineOxygen 2.25 × 10⁻⁷ 2.69 × 10⁻⁷ 7.40 × 10⁻⁷ >99.5 Example B-45 PZT + Si5% Acetylacetonate Diethanolamine Oxygen 2.31 × 10⁻⁷ 2.81 × 10⁻⁷ 7.25 ×10⁻⁷ >99.5 Example B-46 PLZT + Si 0.5% 2-ethyl hexanoate DiethanolamineOxygen 7.38 × 10⁻⁸ 2.10 × 10⁻⁷ 1.21 × 10⁻⁶ 84.5 Example B-47 PLZT + Si0.5% 2-ethyl butyrate Diethanolamine Oxygen 7.21 × 10⁻⁸ 2.31 × 10⁻⁷ 1.13× 10⁻⁶ 85.0 Example B-48 PLZT + Si 0.5% Ethoxide Diethanolamine Oxygen7.35 × 10⁻⁸ 2.25 × 10⁻⁷ 1.18 × 10⁻⁶ 85.0 Example B-49 PLZT + Si 0.5%n-butoxide Diethanolamine Oxygen 7.50 × 10⁻⁸ 2.23 × 10⁻⁷ 1.25 × 10⁻⁶84.5 Example B-50 PLZT + Si 0.5% Acetylacetonate Diethanolamine Oxygen7.43 × 10⁻⁸ 2.18 × 10⁻⁷ 1.23 × 10⁻⁶ 84.0 Comparative Non dope —Diethanolamine Oxygen 8.21 × 10⁻⁷ 1.03 × 10⁻⁵ 2.12 × 10⁻⁴ 70.5 ExampleB-3 PZT (110/52/48) Comparative Non dope — Diethanolamine Oxygen 1.02 ×10⁻⁷ 4.63 × 10⁻⁷ 6.51 × 10⁻⁶ 72.0 Example B-4 PLZT (110/3/52/48)

TABLE 6 Dielectric Addition element Added P strength species/Additive(Phosphorus) Added Baking Leakage current density (A/cm²) voltage amount(mol %) compound form stabilizer atmosphere at 5 V at 20 V at 50 V (V)Example B-51 PZT + Si 0.5% 2-ethyl hexanoate Acetylacetone Dry air 5.92× 10⁻⁷ 2.91 × 10⁻⁶ 1.91 × 10⁻⁵ 78.0 Example B-52 PZT + Si 0.5% 2-ethylbutyrate Acetylacetone Dry air 5.80 × 10⁻⁷ 2.88 × 10⁻⁶ 1.95 × 10⁻⁵ 80.0Example B-53 PZT + Si 0.5% Ethoxide Acetylacetone Dry air 5.83 × 10⁻⁷3.01 × 10⁻⁶ 1.83 × 10⁻⁵ 78.5 Example B-54 PZT + Si 0.5% n-butoxideAcetylacetone Dry air 5.85 × 10⁻⁷ 2.85 × 10⁻⁶ 1.79 × 10⁻⁵ 78.0 ExampleB-55 PZT + Si 0.5% Acetylacetonate Acetylacetone Dry air 6.00 × 10⁻⁷2.81 × 10⁻⁶ 1.97 × 10⁻⁵ 79.0 Example B-56 PZT + Si 1% 2-ethyl hexanoateAcetylacetone Dry air 3.69 × 10⁻⁷ 6.53 × 10⁻⁷ 3.28 × 10⁻⁶ 89.0 ExampleB-57 PZT + Si 1% 2-ethyl butyrate Acetylacetone Dry air 3.83 × 10⁻⁷ 6.35× 10⁻⁷ 3.31 × 10⁻⁶ 87.5 Example B-58 PZT + Si 1% Ethoxide AcetylacetoneDry air 3.85 × 10⁻⁷ 6.41 × 10⁻⁷ 3.41 × 10⁻⁶ 88.0 Example B-59 PZT + Si1% n-butoxide Acetylacetone Dry air 3.61 × 10⁻⁷ 6.31 × 10⁻⁷ 3.35 × 10⁻⁶88.0 Example B-60 PZT + Si 1% Acetylacetonate Acetylacetone Dry air 3.75× 10⁻⁷ 6.61 × 10⁻⁷ 3.25 × 10⁻⁶ 89.0 Example B-61 PZT + Si 3% 2-ethylhexanoate Acetylacetone Dry air 2.48 × 10⁻⁷ 4.25 × 10⁻⁷ 1.51 × 10⁻⁶ 96.0Example B-62 PZT + Si 3% 2-ethyl butyrate Acetylacetone Dry air 2.51 ×10⁻⁷ 4.11 × 10⁻⁷ 1.38 × 10⁻⁶ 97.0 Example B-63 PZT + Si 3% EthoxideAcetylacetone Dry air 2.40 × 10⁻⁷ 4.08 × 10⁻⁷ 1.48 × 10⁻⁶ 95.5 ExampleB-64 PZT + Si 3% n-butoxide Acetylacetone Dry air 2.31 × 10⁻⁷ 4.15 ×10⁻⁷ 1.43 × 10⁻⁶ 96.0 Example B-65 PZT + Si 3% AcetylacetonateAcetylacetone Dry air 2.43 × 10⁻⁷ 4.28 × 10⁻⁷ 1.33 × 10⁻⁶ 97.0 ExampleB-66 PZT + Si 5% 2-ethyl hexanoate Acetylacetone Dry air 2.51 × 10⁻⁷2.86 × 10⁻⁷ 7.35 × 10⁻⁷ >99.5 Example B-67 PZT + Si 5% 2-ethyl butyrateAcetylacetone Dry air 2.53 × 10⁻⁷ 2.73 × 10⁻⁷ 7.26 × 10⁻⁷ >99.5 ExampleB-68 PZT + Si 5% Ethoxide Acetylacetone Dry air 2.45 × 10⁻⁷ 2.69 × 10⁻⁷7.21 × 10⁻⁷ >99.5 Example B-69 PZT + Si 5% n-butoxide Acetylacetone Dryair 2.50 × 10⁻⁷ 2.80 × 10⁻⁷ 7.32 × 10⁻⁷ >99.5 Example B-70 PZT + Si 5%Acetylacetonate Acetylacetone Dry air 2.61 × 10⁻⁷ 2.83 × 10⁻⁷ 7.13 ×10⁻⁷ >99.5 Example B-71 PLZT + Si 0.5% 2-ethyl hexanoate AcetylacetoneDry air 7.25 × 10⁻⁸ 2.13 × 10⁻⁷ 1.21 × 10⁻⁶ 85.0 Example B-72 PLZT + Si0.5% 2-ethyl butyrate Acetylacetone Dry air 7.31 × 10⁻⁸ 2.28 × 10⁻⁷ 1.26× 10⁻⁶ 84.0 Example B-73 PLZT + Si 0.5% Ethoxide Acetylacetone Dry air7.38 × 10⁻⁸ 2.05 × 10⁻⁷ 1.31 × 10⁻⁶ 85.0 Example B-74 PLZT + Si 0.5%n-butoxide Acetylacetone Dry air 7.35 × 10⁻⁸ 2.30 × 10⁻⁷ 1.28 × 10⁻⁶84.5 Example B-75 PLZT + Si 0.5% Acetylacetonate Acetylacetone Dry air7.40 × 10⁻⁸ 2.21 × 10⁻⁷ 1.09 × 10⁻⁶ 84.0 Comparative Non dope —Acetylacetone Dry air 8.52 × 10⁻⁷ 9.85 × 10⁻⁴ 2.16 × 10⁻⁴ 72.0 ExampleB-5 PZT (110/52/48) Comparative Non dope — Acetylacetone Dry air 9.82 ×10⁻⁸ 4.82 × 10⁻⁷ 6.55 × 10⁻⁶ 71.5 Example B-6 PLZT (110/3/52/48)As can be seen from Tables 4 to 6 and FIGS. 5 to 11, the PZTferroelectric thin films of Examples B-1 to B-20, B-26 to B-45, and B-51to B-70 with an addition of Si exhibited a decrease in leakage currentdensity and simultaneously an improvement in dielectric strengthvoltage, as compared to the PZT ferroelectric thin films of ComparativeExamples B-1, B-3 and B-5 with no addition of Si.

Further, the same tendency was also observed from the comparison betweenthe PLZT ferroelectric thin films of Comparative Examples B-2, B-4 andB-6 with an addition of La and the PLZT ferroelectric thin films ofExamples B-21 to B-25, B-46 to B-50, and B-71 to B-75 with theco-addition of Si and La.

From these results, it can be seen that the ferroelectric thin films ofExamples B-1 to B-75 are excellent in leakage current density anddielectric strength voltage. Further, when the ferroelectric thin filmsof Examples B-1 to B-75 are configured to have a leakage current densityequivalent to that of the ferroelectric thin films of ComparativeExamples B-1 to B-6, there are advantages in that the thickness of thefilm can be further reduced, and a higher specific permittivity can beobtained due to thickness reduction of the film. In addition, the amountof raw materials to be used can also be reduced.

The ferroelectric thin films prepared in Examples B-1 to B-75 exhibitexcellent basic characteristics as a capacitor, and can be used for acapacitor with a high density and a high dielectric breakdown voltage.

Hereinafter, Examples C-1 to C-51 of the present invention inconjunction with Comparative Examples C-1 to C-6 will be described inmore detail.

Examples C-1 to C-5

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various cerium compounds (cerium 2-ethylhexanoate, cerium 2-ethyl butyrate, cerium triethoxide, ceriumtri-n-butoxide, tris(acetylacetonate) cerium) was added to these sol-gelliquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples C-6 to C-10

Ferroelectric thin films were formed on substrates in the same manner asin Examples C-1 to C-5, except that 1.0 mol % (in outer percent) ofvarious cerium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples C-11 to C-15

Ferroelectric thin films were formed on substrates in the same manner asin Examples C-1 to C-5, except that 3.0 mol % (in outer percent) ofvarious cerium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Example C-16

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-1 to C-5, except that 1.0 mol % (in outer percent) of alanthanum compound (lanthanum acetate 1.5 hydrate) and 1.0 mol % (inouter percent) of a cerium compound (cerium 2-ethyl hexanoate) wereadded to the sol-gel liquid to prepare a thin film-forming solution.

Example C-17

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-1 to C-5, except that 1.0 mol % (in outer percent) of alanthanum compound (lanthanum acetate 1.5 hydrate) and 1.0 mol % (inouter percent) of a cerium compound (cerium triethoxide) were added tothe sol-gel liquid to prepare a thin film-forming solution.

Comparative Example C-1

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-1 to C-5, except that a thin film-forming solution wasprepared with no addition of cerium compounds to the sol-gel liquid.

Comparative Example C-2

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-1 to C-5, except that a thin film-forming solution wasprepared with no addition of cerium compounds to the sol-gel liquid, butwith addition of 1.0 mol % (in outer percent) of a lanthanum compound(lanthanum acetate 1.5 hydrate).

Examples C-18 to C-22

First, zirconium tetra-n-butoxide and diethanolamine (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide anddiethanolamine (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various cerium compounds (cerium 2-ethylhexanoate, cerium 2-ethyl butyrate, cerium triethoxide, ceriumtri-n-butoxide, tris(acetylacetonate) cerium) was added to these sol-gelliquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples C-23 to C-27

Ferroelectric thin films were formed on substrates in the same manner asin Examples C-18 to C-22, except that 1.0 mol % (in outer percent) ofvarious cerium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples C-28 to C-32

Ferroelectric thin films were formed on substrates in the same manner asin Examples C-18 to C-22, except that 3.0 mol % (in outer percent) ofvarious cerium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Example C-33

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-18 to C-22, except that 1.0 mol % (in outer percent) ofa lanthanum compound (lanthanum acetate 1.5 hydrate) and 1.0 mol % (inouter percent) of a cerium compound (cerium 2-ethyl hexanoate) wereadded to the sol-gel liquid to prepare a thin film-forming solution.

Example C-34

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-18 to C-22, except that 1.0 mol % (in outer percent) ofa lanthanum compound (lanthanum acetate 1.5 hydrate) and 1.0 mol % (inouter percent) of a cerium compound (cerium triethoxide) were added tothe sol-gel liquid to prepare a thin film-forming solution.

Comparative Example C-3

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-18 to C-22, except that a thin film-forming solutionwas prepared with no addition of cerium compounds to the sol-gel liquid.

Comparative Example C-4

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-18 to C-22, except that a thin film-forming solutionwas prepared with no addition of cerium compounds to the sol-gel liquid,but with addition of 1.0 mol % (in outer percent) of a lanthanumcompound (lanthanum acetate 1.5 hydrate).

Examples C-35 to C-39

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various cerium compounds (cerium 2-ethylhexanoate, cerium 2-ethyl butyrate, cerium triethoxide, ceriumtri-n-butoxide, tris(acetylacetonate) cerium) was added to these sol-gelliquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a dry air atmosphere at 700° C. for 1 minute, thereby forming aferroelectric thin film having a film thickness of 270 nm.

Examples C-40 to C-44

Ferroelectric thin films were formed on substrates in the same manner asin Examples C-35 to C-39, except that 1.0 mol % (in outer percent) ofvarious cerium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples C-45 to C-49

Ferroelectric thin films were formed on substrates in the same manner asin Examples C-35 to C-39, except that 3.0 mol % (in outer percent) ofvarious cerium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Example C-50

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-35 to C-39, except that 1.0 mol % (in outer percent) ofa lanthanum compound (lanthanum acetate 1.5 hydrate) and 1.0 mol % (inouter percent) of a cerium compound (cerium 2-ethyl hexanoate) wereadded to the sol-gel liquid to prepare a thin film-forming solution.

Example C-51

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-35 to C-39, except that 1.0 mol % (in outer percent) ofa lanthanum compound (lanthanum acetate 1.5 hydrate) and 1.0 mol % (inouter percent) of a cerium compound (cerium triethoxide) were added tothe sol-gel liquid to prepare a thin film-forming solution.

Comparative Example C-5

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-35 to C-39, except that a thin film-forming solutionwas prepared with no addition of cerium compounds to the sol-gel liquid.

Comparative Example C-6

A ferroelectric thin film was formed on a substrate in the same manneras in Examples C-35 to C-39, except that a thin film-forming solutionwas prepared with no addition of cerium compounds to the sol-gel liquid,but with addition of 1.0 mol % (in outer percent) of a lanthanumcompound (lanthanum acetate 1.5 hydrate).

Comparative Evaluation

For a substrate on which each of the ferroelectric thin films preparedin Examples C-1 to C-51 and Comparative Examples C-1 to C-6 was formed,a Pt upper electrode of about 250 μm was fabricated on the surface ofthe substrate by a sputtering method using a metal mask, a DC voltagewas applied between Pt lower electrodes immediately under theferroelectric thin film, and I-V characteristics (voltage dependence ofleakage current density) were evaluated. In addition, C-Vcharacteristics (voltage dependence of capacitance) were evaluated at afrequency of 1 kHz and at a voltage of −5 to 5 V, between Pt lowerelectrodes immediately under the ferroelectric thin film. The specificpermittivity εr was calculated from the maximum value of capacitance.The results obtained are given in Tables 7 to 9 below, respectively. Themeasurement of I-V characteristics was carried out using a 236 SMU(manufactured by Keithley) under the conditions of Bias step 0.5 V,Delay time 0.1 sec, Temperature 23° C., and Hygrometry 50±10%. Themeasurement of C-V characteristics was carried out using a 4284Aprecision LCR meter (manufactured by HP) under the conditions of a biasstep of 0.1 V, a frequency of 1 kHz, an oscillation level of 30 mV, adelay time of 0.2 sec, a temperature of 23° C., and a hygrometry of50±10%.

TABLE 7 Addition element Specific Leakage current species/Additive AddedCe Added Baking Capacitance permittivity density (A/cm²) amount (mol %)compound form stabilizer atmosphere (μF/cm²) εr at 5 V at 20 V ExampleC-1 Ce 0.5% 2-ethyl hexanoate Acetylacetone Oxygen 4.91 1500 2.37 × 10⁻⁷4.32 × 10⁻⁷ Example C-2 Ce 0.5% 2-ethyl butyrate Acetylacetone Oxygen4.85 1480 2.16 × 10⁻⁷ 4.57 × 10⁻⁷ Example C-3 Ce 0.5% EthoxideAcetylacetone Oxygen 4.92 1500 2.41 × 10⁻⁷ 4.24 × 10⁻⁷ Example C-4 Ce0.5% n-butoxide Acetylacetone Oxygen 4.88 1490 2.05 × 10⁻⁷ 4.79 × 10⁻⁷Example C-5 Ce 0.5% Acetylacetonate Acetylacetone Oxygen 4.79 1460 1.97× 10⁻⁷ 4.19 × 10⁻⁷ Example C-6 Ce 1% 2-ethyl hexanoate AcetylacetoneOxygen 5.09 1550 1.65 × 10⁻⁷ 1.95 × 10⁻⁷ Example C-7 Ce 1% 2-ethylbutyrate Acetylacetone Oxygen 5.13 1570 1.89 × 10⁻⁷ 1.88 × 10⁻⁷ ExampleC-8 Ce 1% Ethoxide Acetylacetone Oxygen 5.01 1530 1.97 × 10⁻⁷ 1.79 ×10⁻⁷ Example C-9 Ce 1% n-butoxide Acetylacetone Oxygen 4.98 1520 1.61 ×10⁻⁷ 2.02 × 10⁻⁷ Example C-10 Ce 1% Acetylacetonate Acetylacetone Oxygen4.99 1520 1.58 × 10⁻⁷ 1.96 × 10⁻⁷ Example C-11 Ce 3% 2-ethyl hexanoateAcetylacetone Oxygen 4.35 1330 1.81 × 10⁻⁷ 2.26 × 10⁻⁷ Example C-12 Ce3% 2-ethyl butyrate Acetylacetone Oxygen 4.38 1340 2.03 × 10⁻⁷ 2.15 ×10⁻⁷ Example C-13 Ce 3% Ethoxide Acetylacetone Oxygen 4.26 1300 2.31 ×10⁻⁷ 2.06 × 10⁻⁷ Example C-14 Ce 3% n-butoxide Acetylacetone Oxygen 4.521380 2.15 × 10⁻⁷ 2.08 × 10⁻⁷ Example C-15 Ce 3% AcetylacetonateAcetylacetone Oxygen 4.35 1330 2.05 × 10⁻⁷ 2.11 × 10⁻⁷ Example C-16 Ce1%, La 1% 2-ethyl hexanoate Acetylacetone Oxygen 5.12 1560 1.55 × 10⁻⁷1.98 × 10⁻⁷ Example C-17 Ce 1%, La 1% Ethoxide Acetylacetone Oxygen 5.171570 1.67 × 10⁻⁷ 2.03 × 10⁻⁷ Comparative Non dope — Acetylacetone Oxygen5.02 1530 8.08 × 10⁻⁷ 1.00 × 10⁻⁵ Example C-1 PZT (110/52/48)Comparative La 1% — Acetylacetone Oxygen 5.27 1610 2.61 × 10⁻⁷ 2.17 ×10⁻⁶ Example C-2

TABLE 8 Addition element Specific Leakage current species/Additive AddedCe Added Baking Capacitance permittivity density (A/cm²) amount (mol %)compound form stabilizer atmosphere (μF/cm²) εr at 5 V at 20 V ExampleC-18 Ce 0.5% 2-ethyl hexanoate Diethanolamine Oxygen 4.88 1490 2.21 ×10⁻⁷ 4.57 × 10⁻⁷ Example C-19 Ce 0.5% 2-ethyl butyrate DiethanolamineOxygen 4.88 1490 2.02 × 10⁻⁷ 4.35 × 10⁻⁷ Example C-20 Ce 0.5% EthoxideDiethanolamine Oxygen 4.94 1510 2.26 × 10⁻⁷ 4.12 × 10⁻⁷ Example C-21 Ce0.5% n-butoxide Diethanolamine Oxygen 4.91 1500 2.15 × 10⁻⁷ 4.33 × 10⁻⁷Example C-22 Ce 0.5% Acetylacetonate Diethanolamine Oxygen 4.91 15002.08 × 10⁻⁷ 4.47 × 10⁻⁷ Example C-23 Ce 1% 2-ethyl hexanoateDiethanolamine Oxygen 5.11 1560 1.71 × 10⁻⁷ 1.80 × 10⁻⁷ Example C-24 Ce1% 2-ethyl butyrate Diethanolamine Oxygen 5.07 1550 1.86 × 10⁻⁷ 1.92 ×10⁻⁷ Example C-25 Ce 1% Ethoxide Diethanolamine Oxygen 5.07 1550 1.86 ×10⁻⁷ 1.92 × 10⁻⁷ Example C-26 Ce 1% n-butoxide Diethanolamine Oxygen5.04 1540 1.81 × 10⁻⁷ 2.01 × 10⁻⁷ Example C-27 Ce 1% AcetylacetonateDiethanolamine Oxygen 5.04 1540 1.78 × 10⁻⁷ 1.91 × 10⁻⁷ Example C-28 Ce3% 2-ethyl hexanoate Diethanolamine Oxygen 4.48 1370 2.18 × 10⁻⁷ 2.03 ×10⁻⁷ Example C-28 Ce 3% 2-ethyl butyrate Diethanolamine Oxygen 4.48 13702.25 × 10⁻⁷ 2.06 × 10⁻⁷ Example C-30 Ce 3% Ethoxide DiethanolamineOxygen 4.52 1380 2.20 × 10⁻⁷ 2.12 × 10⁻⁷ Example C-31 Ce 3% n-butoxideDiethanolamine Oxygen 4.45 1360 2.13 × 10⁻⁷ 2.15 × 10⁻⁷ Example C-32 Ce3% Acetylacetonate Diethanolamine Oxygen 4.45 1360 2.05 × 10⁻⁷ 2.18 ×10⁻⁷ Example C-33 Ce 1%, La 1% 2-ethyl hexanoate Diethanolamine Oxygen5.14 1570 1.61 × 10⁻⁷ 1.93 × 10⁻⁷ Example C-34 Ce 1%, La 1% EthoxideDiethanolamine Oxygen 5.14 1570 1.53 × 10⁻⁷ 2.09 × 10⁻⁷ Comparative Nondope — Diethanolamine Oxygen 4.94 1510 8.51 × 10⁻⁷ 1.04 × 10⁻⁵ ExampleC-3 PZT (110/52/48) Comparative La 1% — Diethanolamine Oxygen 5.20 15902.65 × 10⁻⁷ 2.31 × 10⁻⁶ Example C-4

TABLE 9 Addition element Specific Leakage current species/Additive AddedCe Added Baking Capacitance permittivity density (A/cm²) amount (mol %)compound form stabilizer atmosphere (μF/cm²) εr at 5 V at 20 V ExampleC-35 Ce 0.5% 2-ethyl hexanoate Acetylacetone Dry air 4.94 1510 2.15 ×10⁻⁷ 4.72 × 10⁻⁷ Example C-36 Ce 0.5% 2-ethyl butyrate Acetylacetone Dryair 4.88 1490 2.03 × 10⁻⁷ 4.20 × 10⁻⁷ Example C-37 Ce 0.5% EthoxideAcetylacetone Dry air 4.84 1480 2.21 × 10⁻⁷ 4.65 × 10⁻⁷ Example C-38 Ce0.5% n-butoxide Acetylacetone Dry air 4.88 1490 2.09 × 10⁻⁷ 4.50 × 10⁻⁷Example C-39 Ce 0.5% Acetylacetonate Acetylacetone Dry air 4.88 14902.29 × 10⁻⁷ 4.33 × 10⁻⁷ Example C-40 Ce 1% 2-ethyl hexanoateAcetylacetone Dry air 5.07 1550 1.65 × 10⁻⁷ 1.93 × 10⁻⁷ Example C-41 Ce1% 2-ethyl butyrate Acetylacetone Dry air 5.11 1560 1.90 × 10⁻⁷ 1.85 ×10⁻⁷ Example C-42 Ce 1% Ethoxide Acetylacetone Dry air 5.01 1530 1.60 ×10⁻⁷ 2.00 × 10⁻⁷ Example C-43 Ce 1% n-butoxide Acetylacetone Dry air5.01 1530 2.05 × 10⁻⁷ 1.80 × 10⁻⁷ Example C-44 Ce 1% AcetylacetonateAcetylacetone Dry air 5.14 1570 1.83 × 10⁻⁷ 1.72 × 10⁻⁷ Example C-45 Ce3% 2-ethyl hexanoate Acetylacetone Dry air 4.39 1340 2.13 × 10⁻⁷ 2.18 ×10⁻⁷ Example C-46 Ce 3% 2-ethyl butyrate Acetylacetone Dry air 4.48 13702.03 × 10⁻⁷ 2.09 × 10⁻⁷ Example C-47 Ce 3% Ethoxide Acetylacetone Dryair 4.42 1350 1.92 × 10⁻⁷ 2.03 × 10⁻⁷ Example C-48 Ce 3% n-butoxideAcetylacetone Dry air 4.42 1350 1.95 × 10⁻⁷ 1.98 × 10⁻⁷ Example C-49 Ce3% Acetylacetonate Acetylacetone Dry air 4.39 1340 1.98 × 10⁻⁷ 2.01 ×10⁻⁷ Example C-50 Ce 1%, La 1% 2-ethyl hexanoate Acetylacetone Dry air5.07 1550 1.63 × 10⁻⁷ 2.05 × 10⁻⁷ Example C-51 Ce 1%, La 1% EthoxideAcetylacetone Dry air 5.07 1550 1.81 × 10⁻⁷ 1.98 × 10⁻⁷ Comparative Nondope — Acetylacetone Dry air 4.94 1510 8.31 × 10⁻⁷ 1.07 × 10⁻⁵ ExampleC-5 PZT (110/52/48) Comparative La 1% — Acetylacetone Dry air 5.17 15802.73 × 10⁻⁷ 2.26 × 10⁻⁶ Example C-6

As can be seen from Tables 7 to 9, the ferroelectric thin films ofExamples C-1 to C-51 with an addition of Ce exhibited a lower leakagecurrent density at a thin film thickness of about 270 nm, as compared tothe PZT ferroelectric thin films of Comparative Examples C-1 to C-6 withno addition of Ce.

In addition, from the comparison with the PLZT ferroelectric thin filmsof Comparative Examples C-2, C-4, and C-6 with an addition of La, allexhibited a decrease in leakage current density, upon application of 5 Vand 20 V.

With regard to capacitance and specific permittivity, upon comparisonwith the ferroelectric thin films of Comparative Examples C-1 to C-6,the ferroelectric thin films of Examples C-1 to C-51 also exhibited somecases of slight low values which are generally, however, not inferiorresults. It can be said that the resulting numerical values are in noway inferior to those of conventionally known ferroelectric thin films.

However, when the ferroelectric thin films of Examples C-1 to B-51 areconfigured to have a leakage current density equivalent to that of theferroelectric thin films of Comparative Examples C-1 to C-6, there areadvantages in that the thickness of the film can be further reduced, anda higher specific permittivity can be obtained due to thicknessreduction of the film.

From these results, the ferroelectric thin films of Examples C-1 to C-51are excellent in reduction of a leakage current density without adecrease in specific permittivity, and can achieve a high capacitydensity from the viewpoint of being capable of realizing thicknessreduction of the film.

The ferroelectric thin films prepared in Examples C-1 to C-51 exhibitexcellent basic characteristics as a capacitor, and can be used for acapacitor with a high density and a high dielectric breakdown voltage.

Hereinafter, Examples D-1 to D-75 of the present invention inconjunction with Comparative Examples D-1 to D-3 will be described inmore detail.

Examples D-1 to D-5

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various bismuth compounds (bismuth 2-ethylhexanoate, bismuth 2-ethyl butyrate, bismuth triisopropoxide, bismuthtri-t-pentoxide, tetra(methyl heptanedionate) bismuth) was added tothese sol-gel liquids, thereby obtaining five thin film-formingsolutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples D-6 to D-10

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-1 to D-5, except that 1.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples D-11 to D-15

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-1 to D-5, except that 3.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples D-16 to D-20

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-1 to D-5, except that 5.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples D-21 to D-25

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-1 to D-5, except that 10.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example D-1

A ferroelectric thin film was formed on a substrate in the same manneras in Examples D-1 to D-5, except that a thin film-forming solution wasprepared with no addition of bismuth compounds to the sol-gel liquid ofExample D-1.

Examples D-26 to D-30

First, zirconium tetra-n-butoxide and diethanolamine (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide anddiethanolamine (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various bismuth compounds (bismuth 2-ethylhexanoate, bismuth 2-ethyl butyrate, bismuth triisopropoxide, bismuthtri-t-pentoxide, tetra(methyl heptanedionate) bismuth) was added tothese sol-gel liquids, thereby obtaining five thin film-formingsolutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples D-31 to D-35

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-26 to D-30, except that 1.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples D-36 to D-40

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-26 to D-30, except that 3.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples D-41 to D-45

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-26 to D-30, except that 5.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples D-46 to D-50

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-26 to D-30, except that 10.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example D-2

A ferroelectric thin film was formed on a substrate in the same manneras in Examples D-26 to D-30, except that a thin film-forming solutionwas prepared with no addition of bismuth compounds to the sol-gel liquidof Example D-26.

Examples D-51 to D-55

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various bismuth compounds (bismuth 2-ethylhexanoate, bismuth 2-ethyl butyrate, bismuth triisopropoxide, bismuthtri-t-pentoxide, tetra(methyl heptanedionate) bismuth) was added tothese sol-gel liquids, thereby obtaining five thin film-formingsolutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a dry air atmosphere at 700° C. for 1 minute, thereby forming aferroelectric thin film having a film thickness of 270 nm.

Examples D-56 to D-60

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-51 to D-55, except that 1.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples D-61 to D-65

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-51 to D-55, except that 3.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples D-66 to D-70

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-51 to D-55, except that 5.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples D-71 to D-75

Ferroelectric thin films were formed on substrates in the same manner asin Examples D-51 to D-55, except that 10.0 mol % (in outer percent) ofvarious bismuth compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example D-3

A ferroelectric thin film was formed on a substrate in the same manneras in Examples D-51 to D-55, except that a thin film-forming solutionwas prepared with no addition of bismuth compounds to the sol-gel liquidof Example D-51.

Comparative Evaluation

For a substrate on which each of the ferroelectric thin films preparedin Examples D-1 to D-75 and Comparative Examples D-1 to D-3 was formed,a Pt upper electrode of about 250 μm□ was fabricated on the surface ofthe substrate by a sputtering method using a metal mask, and C-Vcharacteristics (voltage dependence of capacitance) were evaluated at afrequency of 1 kHz and at a voltage of −5 to 5 V, between Pt lowerelectrodes immediately under the ferroelectric thin film. The specificpermittivity εr was calculated from the maximum value of capacitance.The measurement of C-V characteristics was carried out using a 4284Aprecision LCR meter (manufactured by HP) under the conditions of a biasstep 0.1 of V, a frequency of 1 kHz, an oscillation level of 30 mV, adelay time of 0.2 sec, a temperature of 23° C., and a hygrometry of50±10%. The results obtained are given in Tables 10 to 12 below.

TABLE 10 Addition element Specific species/Additive Added Bi AddedBaking Capacitance permittivity amount (mol %) compound form stabilizeratmosphere (μF/cm²) εr Example D-1 Bi 0.5% 2-ethyl hexanoateAcetylacetone Oxygen 5.24 1590 Example D-2 Bi 0.5% 2-ethyl butyrateAcetylacetone Oxygen 5.17 1570 Example D-3 Bi 0.5% IsopropoxideAcetylacetone Oxygen 5.21 1580 Example D-4 Bi 0.5% t-pentoxideAcetylacetone Oxygen 5.21 1580 Example D-5 Bi 0.5% TetramethylAcetylacetone Oxygen 5.21 1580 heptanedionate Example D-6 Bi 1% 2-ethylhexanoate Acetylacetone Oxygen 5.22 1580 Example D-7 Bi 1% 2-ethylbutyrate Acetylacetone Oxygen 5.27 1600 Example D-8 Bi 1% IsopropoxideAcetylacetone Oxygen 5.21 1580 Example D-9 Bi 1% t-pentoxideAcetylacetone Oxygen 5.24 1590 Example D-10 Bi 1% TetramethylAcetylacetone Oxygen 5.24 1590 heptanedionate Example D-11 Bi 3% 2-ethylhexanoate Acetylacetone Oxygen 5.84 1780 Example D-12 Bi 3% 2-ethylbutyrate Acetylacetone Oxygen 5.93 1800 Example D-13 Bi 3% IsopropoxideAcetylacetone Oxygen 5.93 1800 Example D-14 Bi 3% t-pentoxideAcetylacetone Oxygen 5.90 1790 Example D-15 Bi 3% TetramethylAcetylacetone Oxygen 5.87 1780 heptanedionate Example D-16 Bi 5% 2-ethylhexanoate Acetylacetone Oxygen 6.20 1880 Example D-17 Bi 5% 2-ethylbutyrate Acetylacetone Oxygen 6.20 1880 Example D-18 Bi 5% IsopropoxideAcetylacetone Oxygen 6.16 1870 Example D-19 Bi 5% t-pentoxideAcetylacetone Oxygen 6.20 1880 Example D-20 Bi 5% TetramethylAcetylacetone Oxygen 6.20 1880 heptanedionate Example D-21 Bi 10%2-ethyl hexanoate Acetylacetone Oxygen 5.77 1750 Example D-22 Bi 10%2-ethyl butyrate Acetylacetone Oxygen 5.77 1750 Example D-23 Bi 10%Isopropoxide Acetylacetone Oxygen 5.80 1760 Example D-24 Bi 10%t-pentoxide Acetylacetone Oxygen 5.80 1760 Example D-25 Bi 10%Tetramethyl Acetylacetone Oxygen 5.83 1770 heptanedionate ComparativeNon dope — Acetylacetone Oxygen 5.07 1540 Example D-1 PZT (110/52/48)

TABLE 11 Addition element Specific species/Additive Added Bi AddedBaking Capacitance permittivity amount (mol %) compound form stabilizeratmosphere (μF/cm²) εr Example D-26 Bi 0.5% 2-ethyl hexanoateDiethanolamine Oxygen 5.17 1570 Example D-27 Bi 0.5% 2-ethyl butyrateDiethanolamine Oxygen 5.14 1560 Example D-28 Bi 0.5% IsopropoxideDiethanolamine Oxygen 5.17 1570 Example D-29 Bi 0.5% t-pentoxideDiethanolamine Oxygen 5.20 1580 Example D-30 Bi 0.5% TetramethylDiethanolamine Oxygen 5.20 1580 heptanedionate Example D-31 Bi 1%2-ethyl hexanoate Diethanolamine Oxygen 5.27 1600 Example D-32 Bi 1%2-ethyl butyrate Diethanolamine Oxygen 5.27 1600 Example D-33 Bi 1%Isopropoxide Diethanolamine Oxygen 5.23 1590 Example D-34 Bi 1%t-pentoxide Diethanolamine Oxygen 5.23 1590 Example D-35 Bi 1%Tetramethyl Diethanolamine Oxygen 5.23 1590 heptanedionate Example D-36Bi 3% 2-ethyl hexanoate Diethanolamine Oxygen 5.93 1800 Example D-37 Bi3% 2-ethyl butyrate Diethanolamine Oxygen 5.93 1800 Example D-38 Bi 3%Isopropoxide Diethanolamine Oxygen 5.89 1790 Example D-39 Bi 3%t-pentoxide Diethanolamine Oxygen 5.93 1800 Example D-40 Bi 3%Tetramethyl Diethanolamine Oxygen 5.89 1790 heptanedionate Example D-41Bi 5% 2-ethyl hexanoate Diethanolamine Oxygen 6.26 1900 Example D-42 Bi5% 2-ethyl butyrate Diethanolamine Oxygen 6.22 1890 Example D-43 Bi 5%Isopropoxide Diethanolamine Oxygen 6.26 1900 Example D-44 Bi 5%t-pentoxide Diethanolamine Oxygen 6.29 1910 Example D-45 Bi 5%Tetramethyl Diethanolamine Oxygen 6.19 1880 heptanedionate Example D-46Bi 10% 2-ethyl hexanoate Diethanolamine Oxygen 5.79 1760 Example D-47 Bi10% 2-ethyl butyrate Diethanolamine Oxygen 5.79 1760 Example D-48 Bi 10%Isopropoxide Diethanolamine Oxygen 5.76 1750 Example D-49 Bi 10%t-pentoxide Diethanolamine Oxygen 5.83 1770 Example D-50 Bi 10%Tetramethyl Diethanolamine Oxygen 5.83 1770 heptanedionate ComparativeNon dope — Diethanolamine Oxygen 5.04 1530 Example D-2 PZT (110/52/48)

TABLE 12 Addition element Specific species/Additive Added Bi AddedBaking Capacitance permittivity amount (mol %) compound form stabilizeratmosphere (μF/cm²) εr Example D-51 Bi 0.5% 2-ethyl hexanoateAcetylacetone Dry air 5.20 1580 Example D-52 Bi 0.5% 2-ethyl butyrateAcetylacetone Dry air 5.20 1580 Example D-53 Bi 0.5% IsopropoxideAcetylacetone Dry air 5.23 1590 Example D-54 Bi 0.5% t-pentoxideAcetylacetone Dry air 5.17 1570 Example D-55 Bi 0.5% TetramethylAcetylacetone Dry air 5.23 1590 heptanedionate Example D-56 Bi 1%2-ethyl hexanoate Acetylacetone Dry air 5.23 1590 Example D-57 Bi 1%2-ethyl butyrate Acetylacetone Dry air 5.30 1610 Example D-58 Bi 1%Isopropoxide Acetylacetone Dry air 5.30 1610 Example D-59 Bi 1%t-pentoxide Acetylacetone Dry air 5.23 1590 Example D-60 Bi 1%Tetramethyl Acetylacetone Dry air 5.27 1600 heptanedionate Example D-61Bi 3% 2-ethyl hexanoate Acetylacetone Dry air 5.96 1810 Example D-62 Bi3% 2-ethyl butyrate Acetylacetone Dry air 5.89 1790 Example D-63 Bi 3%Isopropoxide Acetylacetone Dry air 5.96 1810 Example D-64 Bi 3%t-pentoxide Acetylacetone Dry air 5.89 1790 Example D-65 Bi 3%Tetramethyl Acetylacetone Dry air 5.89 1790 heptanedionate Example D-66Bi 5% 2-ethyl hexanoate Acetylacetone Dry air 6.22 1890 Example D-67 Bi5% 2-ethyl butyrate Acetylacetone Dry air 6.22 1890 Example D-68 Bi 5%Isopropoxide Acetylacetone Dry air 6.16 1870 Example D-69 Bi 5%t-pentoxide Acetylacetone Dry air 6.16 1870 Example D-70 Bi 5%Tetramethyl Acetylacetone Dry air 6.22 1890 heptanedionate Example D-71Bi 10% 2-ethyl hexanoate Acetylacetone Dry air 5.79 1760 Example D-72 Bi10% 2-ethyl butyrate Acetylacetone Dry air 5.76 1750 Example D-73 Bi 10%Isopropoxide Acetylacetone Dry air 5.83 1770 Example D-74 Bi 10%t-pentoxide Acetylacetone Dry air 5.76 1750 Example D-75 Bi 10%Tetramethyl Acetylacetone Dry air 5.83 1770 heptanedionate ComparativeNon dope — Acetylacetone Dry air 5.03 1530 Example D-3 PZT (110/52/48)

As can be seen from Tables 10 to 12, as compared to the PZTferroelectric thin films of Comparative Examples D-1 to D-3 with noaddition of Bi, the ferroelectric thin films of Examples D-1 to D-75with an addition of Bi at a concentration of 0.5% to 10% exhibited ahigh capacitance and a high specific permittivity at a thin filmthickness of about 270 nm. From these results, it can be seen that theferroelectric thin films of Examples D-1 to D-75 exhibit excellent basiccharacteristics as a capacitor.

In addition, according to the results of the ferroelectric thin films ofExamples D-1 to D-75 with varying additive amounts of Bi, particularlyExamples D-16 to D-20, D-41 to D-45, and D-66 to D-70 with a 5% additionof Bi exhibited high numerical results in terms of capacitance andspecific permittivity, followed by in the order of: Examples D-11 toD-15, D-36 to D-40, and D-61 to D-65 with a 3% addition of Bi; ExamplesD-21 to D-25, D-46 to D-50, and D-71 to D-75 with a 10% addition of Bi;Examples D-6 to D-10, D-31 to D-35, and D-56 to D-60 with a 1% additionof Bi; and Examples D-1 to D-5, D-26 to D-30, and D-51 to D-55 with a0.5% addition of Bi.

From these results, it was demonstrated that there is an appropriaterange of the Bi additive amount capable of contributing to improvementsof the capacitance and specific permittivity cr.

The ferroelectric thin films prepared in Examples D-1 to D-75 exhibitexcellent basic characteristics as a capacitor, and can be used for athin film capacitor with a high capacity density.

[Group 2]

Hereinafter, Examples E-1 to E-27 of the present invention inconjunction with Comparative Examples E-1 to E-8 will be described inmore detail.

The following Examples E-1 to E-27 and Comparative Examples E-1 to E-8were carried out using the raw materials below.

Pb compound: lead acetate trihydrate

La compound: lanthanum acetate 1.5 hydrate

Zr compound: zirconium tetra-t-butoxide

Ti compound: titanium tetraisopropoxide

Sn compound: tin acetate, tin octylate, tin acetate, tintetra-n-butoxide, tin ethoxide

Examples E-1 to E-27 and Comparative Examples E-1 to E-8

An organometallic compound (Pb, La, Sn compound, etc.) in the form of anorganic acid salt and nitrate was dissolved in sufficiently dehydrated2-methoxy ethanol as an organic solvent, and water of crystallizationwas removed by azeotropic distillation. Then, an organometallic compoundor organic compound (Zr, Ti, Sn compound, etc.) in the form of analkoxide was added and dissolved in the resulting solution. For thepurpose of solution stabilization, a 2-fold mol of acetylacetone ordiethanolamine was added relative to the metal alkoxide. Each elementwas added to PZT according to the addition element species and additiveamount as given in Table 13 or 14 below, thereby preparing a solutionfor the formation of a thin film such that the total concentration oforganometallic compounds in terms of the metal oxides was about 10% byweight.

Using each solution, a thin film was formed by a CSD method, accordingto the following procedure.

That is, each solution was applied by a spin coating method at 500 rpmfor 3 seconds and then at 3000 rpm for 15 seconds to a 6 inch siliconsubstrate where a Pt thin film was sputtered on the surface thereof.

Then, pre-baking was carried out by heating the substrate on a hot plateat 350° C. for 10 minutes. After the application and pre-bakingprocesses were repeated 6 times, the substrate was subjected to bakingin a rapid thermal annealer (RTA) under a 100% oxygen atmosphere or dryair atmosphere at 700° C. for 1 minute, thereby forming a ferroelectricthin film having a film thickness of 300 nm.

Next, a Pt upper electrode of about 250 μm□ was fabricated on thesurface of the substrate by a sputtering method using a metal mask, andC-V characteristics (voltage dependence of capacitance) were evaluatedat a frequency of 1 kHz and at a voltage of −5 to 5 V, between Pt lowerelectrodes immediately under the ferroelectric thin film. The specificpermittivity Er was calculated from the maximum value of capacitance.The measurement of C-V characteristics was carried out using a 4284Aprecision LCR meter (manufactured by HP) under the conditions of a biasstep of 0.1 V, a frequency of 1 kHz, an oscillation level of 30 mV, adelay time of 0.2 sec, a temperature of 23° C., and a hygrometry of50±10%. The results obtained are given in Tables 13 and 14 below, andFIG. 12. In addition, C-V curve diagrams of Examples E-2 and E-7 andComparative Example E-1 are given in FIGS. 13 to 15, respectively.

TABLE 13 Addition element Specific species/Additive Added Sn AddedBaking permittivity amount (mol %) compound form stabilizer atmosphereεr C-V curve Example E-1 Sn 0.5% Tin octylate Acetylacetone Oxygen 1600— Example E-2 Sn 1% Tin tetra-n-butoxide Acetylacetone Oxygen 2030 FIG.3 Example E-3 Sn 3% Tin tetra-n-butoxide Acetylacetone Oxygen 1780 —Example E-4 Sn 5% Tin octylate Acetylacetone Oxygen 1620 — Example E-5Sn 1%, Si 0.5% Tin acetate Acetylacetone Oxygen 1820 — Example E-6 Sn1%, P(III) 1% Tin octylate Acetylacetone Oxygen 1820 — Example E-7 Sn1%, P (V) 1% Tin nitrate Acetylacetone Oxygen 2260 FIG. 4 Example E-8 Sn1%, P(V) 5% Tin ethoxide Acetylacetone Oxygen 1820 — Example E-9 Sn 1%Tin 2-ethyl butyrate Acetylacetone Oxygen 1900 — Comparative Non dope —Acetylacetone Oxygen 1540 FIG. 2 Example E-1 PZT (110/52/48) ComparativeLa 3% — Acetylacetone Oxygen 1550 — Example E-2 Comparative Si 0.5% —Acetylacetone Oxygen 1400 — Example E-3 Comparative P(III) 1% —Acetylacetone Oxygen 1470 — Example E-4 Comparative P(V) 5% —Acetylacetone Oxygen 1400 — Example E-5 Comparative Sn 10% Tintetra-n-butoxide Acetylacetone Oxygen 1300 — Example E-6

TABLE 14 Addition element Specific species/Additive Added Sn AddedBaking permittivity amount (mol %) compound form stabilizer atmosphereεr Example E-10 Sn 0.5% Tin octylate Diethanolamine Oxygen 1650 ExampleE-11 Sn 1% Tin octylate Diethanolamine Oxygen 1760 Example E-12 Sn 1%Tin 2-ethyl butyrate Diethanolamine Oxygen 1870 Example E-13 Sn 1% Tinacetate Diethanolamine Oxygen 1820 Example E-14 Sn 1% Tintetra-n-butoxide Diethanolamine Oxygen 1760 Example E-15 Sn 1% Tinethoxide Diethanolamine Oxygen 1770 Example E-16 Sn 1% Tin nitrateDiethanolamine Oxygen 1740 Example E-17 Sn 3% Tin octylateDiethanolamine Oxygen 1680 Example E-18 Sn 5% Tin octylateDiethanolamine Oxygen 1600 Example E-19 Sn 0.5% Tin octylateAcetylacetone Dry air 1640 Example E-20 Sn 1% Tin octylate AcetylacetoneDry air 1800 Example E-21 Sn 1% Tin 2-ethyl butyrate Acetylacetone Dryair 1900 Example E-22 Sn 1% Tin acetate Acetylacetone Dry air 1750Example E-23 Sn 1% Tin tetra-n-butoxide Acetylacetone Dry air 1800Example E-24 Sn 1% Tin ethoxide Acetylacetone Dry air 1720 Example E-25Sn 1% Tin nitrate Acetylacetone Dry air 1660 Example E-26 Sn 3% Tinoctylate Acetylacetone Dry air 1680 Example E-27 Sn 5% Tin octylateAcetylacetone Dry air 1590 Comparative Sn 7% Tin octylate DiethanolamineOxygen 1480 Example E-7 Comparative Sn 10% Tin octylate AcetylacetoneDry air 1320 Example E-8

As can be seen from Tables 13 and 12, as compared to the PZTferroelectric thin film of Comparative Example E-1 and the PLZTferroelectric thin film of Comparative Example E-2, each with noaddition of Sn, the ferroelectric thin films of Examples E-1 to E-9 withan addition of Sn exhibited a high specific permittivity Cr. From theseresults, it was demonstrated that the ferroelectric thin films ofExamples E-1 to E-9 exhibit excellent basic characteristics as acapacitor.

However, the PZT ferroelectric thin film of Comparative Example E-6 witha 10% addition of Sn exhibited results inferior to the PZT ferroelectricthin film of Comparative Example E-1 with no addition of Sn.

In addition, according to the results of the ferroelectric thin films ofExamples E-1 to E-4 and Comparative Example E-6 with varying additiveamounts of Sn, particularly Examples E-2 with a 1% addition of Snexhibited high numerical results in terms of specific permittivity,followed by in the order of: Examples E-3 with a 3% addition of Sn;Example E-1 with a 0.5% addition of Sn and Example E-4 with a 5%addition of Sn, which exhibit substantially the same results; andExamples E-6 with a 10% addition of Sn. From these results, it wasdemonstrated that there is an appropriate range of the Sn additiveamount capable of contributing to improvements of the specificpermittivity Cr.

In addition, as can be seen from the results of the ferroelectric thinfilms of Examples E-5 to E-8 and Comparative Examples E-3 to E-5,coexistence of Sn with another ingredient (such as Si or P) in an amountof about 1% also exhibited favorable effects of Sn. In particular,Example E-7 having coexistence of Sn with P(V) in an amount of about 1%also exhibited a high specific permittivity εr as compared to otherExamples.

Further, as shown Table 14, from the results of the ferroelectric thinfilms of Examples E-10 to E-18 and Comparative Example E-7, it wasdemonstrated that addition effects of Sn were obtained even when thestabilizer was changed to diethanolamine.

Further, from the results of the ferroelectric thin films of ExamplesE-19 to E-27 and Comparative Example E-8, it was demonstrated thataddition effects of Sn were obtained even when the baking atmosphere waschanged to dry air.

The ferroelectric thin films of Examples E-10 to E-27 exhibit excellentbasic characteristics as a capacitor, and can be used for a thin filmcapacitor with a high capacity density.

Hereinafter, Examples F-1 to F-45 of the present invention inconjunction with Comparative Examples F-1 to F-18 will be described inmore detail.

Examples F-1 to F-5

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various samarium compounds (samarium 2-ethylhexanoate, samarium 2-ethyl butyrate, samarium triethoxide, samariumtri-n-butoxide, tris(acetylacetonate) samarium) samarium was added tothese sol-gel liquids, thereby obtaining five thin film-formingsolutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples F-6 to F-10

Ferroelectric thin films were formed on substrates in the same manner asin Examples F-1 to F-5, except that 1.0 mol % (in outer percent) ofvarious samarium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples F-11 to F-15

Ferroelectric thin films were formed on substrates in the same manner asin Examples F-1 to F-5, except that 2.0 mol % (in outer percent) ofvarious samarium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example F-1

A ferroelectric thin film was formed on a substrate in the same manneras in Examples F-1 to F-5, except that a thin film-forming solution wasprepared with no addition of samarium compounds to the sol-gel liquid.

Comparative Examples F-2 to F-6

Ferroelectric thin films were formed on substrates in the same manner asin Examples F-1 to F-5, except that 3.0 mol % (in outer percent) ofvarious samarium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples F-16 to F-20

First, zirconium tetra-n-butoxide and diethanolamine (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide anddiethanolamine (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various samarium compounds (samarium 2-ethylhexanoate, samarium 2-ethyl butyrate, samarium triethoxide, samariumtri-n-butoxide, tris(acetylacetonate) samarium) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples F-21 to F-25

Ferroelectric thin films were formed on substrates in the same manner asin Examples F-16 to F-20, except that 1.0 mol % (in outer percent) ofvarious samarium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples F-26 to F-30

Ferroelectric thin films were formed on substrates in the same manner asin Examples F-16 to F-20, except that 2.0 mol % (in outer percent) ofvarious samarium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example F-7

A ferroelectric thin film was formed on a substrate in the same manneras in Examples F-16 to F-20, except that a thin film-forming solutionwas prepared with no addition of samarium compounds to the sol-gelliquid.

Comparative Examples F-8 to F-12

Ferroelectric thin films were formed on substrates in the same manner asin Examples F-16 to F-20, except that 3.0 mol % (in outer percent) ofvarious samarium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples F-31 to F-35

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various samarium compounds (samarium 2-ethylhexanoate, samarium 2-ethyl butyrate, samarium triethoxide, samariumtri-n-butoxide, tris(acetylacetonate) samarium) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to high-temperature baking in a rapid thermalannealer (RTA) under a dry air atmosphere at 700° C. for 1 minute,thereby forming a ferroelectric thin film having a film thickness of 270nm.

Examples F-36 to F-40

Ferroelectric thin films were formed on substrates in the same manner asin Examples F-31 to F-35, except that 1.0 mol % (in outer percent) ofvarious samarium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples F-41 to F-45

Ferroelectric thin films were formed on substrates in the same manner asin Examples F-31 to F-35, except that 2.0 mol % (in outer percent) ofvarious samarium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example F-13

A ferroelectric thin film was formed on a substrate in the same manneras in Examples F-31 to F-35, except that a thin film-forming solutionwas prepared with no addition of samarium compounds to the sol-gelliquid.

Comparative Examples F-14 to F-18

Ferroelectric thin films were formed on substrates in the same manner asin Examples F-31 to F-35, except that 3.0 mol % (in outer percent) ofvarious samarium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Evaluation

For a substrate on which each of the ferroelectric thin films preparedin Examples F-1 to F-45 and Comparative Examples F-1 to F-18 was formed,a Pt upper electrode of about 25 μm□ was fabricated on the surface ofthe substrate by a sputtering method using a metal mask, and C-Vcharacteristics (voltage dependence of capacitance) were evaluated at afrequency of 1 kHz and at a voltage of −5 to 5 V, between Pt lowerelectrodes immediately under the ferroelectric thin film. The specificpermittivity εr was calculated from the maximum value of capacitance.The measurement of C-V characteristics was carried out using a 4284Aprecision LCR meter (manufactured by HP) under the conditions of a biasstep of 0.1 V, a frequency of 1 kHz, an oscillation level of 30 mV, adelay time of 0.2 sec, a temperature of 23° C., and a hygrometry of50±10%. The results obtained are given in Tables 15 to 17 below.

TABLE 15 Addition element Specific species/Additive Added Sm AddedBaking Capacitance permittivity amount (mol %) compound form stabilizeratmosphere (μF/cm²) εr Example F-1 Sm 0.5% 2-ethyl hexanoateAcetylacetone Oxygen 5.40 1630 Example F-2 Sm 0.5% 2-ethyl butyrateAcetylacetone Oxygen 5.47 1650 Example F-3 Sm 0.5% EthoxideAcetylacetone Oxygen 5.47 1650 Example F-4 Sm 0.5% n-butoxideAcetylacetone Oxygen 5.43 1640 Example F-5 Sm 0.5% AcetylacetonateAcetylacetone Oxygen 5.40 1630 Example F-6 Sm 1% 2-ethyl hexanoateAcetylacetone Oxygen 5.70 1720 Example F-7 Sm 1% 2-ethyl butyrateAcetylacetone Oxygen 5.80 1750 Example F-8 Sm 1% Ethoxide AcetylacetoneOxygen 5.73 1730 Example F-9 Sm 1% n-butoxide Acetylacetone Oxygen 5.701720 Example F-10 Sm 1% Acetylacetonate Acetylacetone Oxygen 5.70 1720Example F-11 Sm 2% 2-ethyl hexanoate Acetylacetone Oxygen 5.96 1800Example F-12 Sm 2% 2-ethyl butyrate Acetylacetone Oxygen 6.03 1820Example F-13 Sm 2% Ethoxide Acetylacetone Oxygen 6.03 1820 Example F-14Sm 2% n-butoxide Acetylacetone Oxygen 5.96 1800 Example F-15 Sm 2%Acetylacetonate Acetylacetone Oxygen 6.00 1810 Comparative Non dope —Acetylacetone Oxygen 5.07 1530 Example F-1 (PZT (110/52/48)) ComparativeSm 3% 2-ethyl hexanoate Acetylacetone Oxygen 4.64 1400 Example F-2Comparative Sm 3% 2-ethyl butyrate Acetylacetone Oxygen 4.61 1390Example F-3 Comparative Sm 3% Ethoxide Acetylacetone Oxygen 4.71 1420Example F-4 Comparative Sm 3% n-butoxide Acetylacetone Oxygen 4.67 1410Example F-5 Comparative Sm 3% Acetylacetonate Acetylacetone Oxygen 4.671410 Example F-6

TABLE 16 Addition element Specific species/Additive Added Sm AddedBaking Capacitance permittivity amount (mol %) compound form stabilizeratmosphere (μF/cm²) εr Example F-16 Sm 0.5% 2-ethyl hexanoateDiethanolamine Oxygen 5.43 1640 Example F-17 Sm 0.5% 2-ethyl butyrateDiethanolamine Oxygen 5.43 1640 Example F-18 Sm 0.5% EthoxideDiethanolamine Oxygen 5.37 1620 Example F-19 Sm 0.5% n-butoxideDiethanolamine Oxygen 5.40 1630 Example F-20 Sm 0.5% AcetylacetonateDiethanolamine Oxygen 5.37 1620 Example F-21 Sm 1% 2-ethyl hexanoateDiethanolamine Oxygen 5.83 1760 Example F-22 Sm 1% 2-ethyl butyrateDiethanolamine Oxygen 5.83 1760 Example F-23 Sm 1% EthoxideDiethanolamine Oxygen 5.80 1750 Example F-24 Sm 1% n-butoxideDiethanolamine Oxygen 5.80 1750 Example F-25 Sm 1% AcetylacetonateDiethanolamine Oxygen 5.73 1730 Example F-26 Sm 2% 2-ethyl hexanoateDiethanolamine Oxygen 6.00 1810 Example F-27 Sm 2% 2-ethyl butyrateDiethanolamine Oxygen 6.00 1810 Example F-28 Sm 2% EthoxideDiethanolamine Oxygen 6.06 1830 Example F-29 Sm 2% n-butoxideDiethanolamine Oxygen 6.03 1820 Example F-30 Sm 2% AcetylacetonateDiethanolamine Oxygen 6.06 1830 Comparative Non dope — DiethanolamineOxygen 5.04 1520 Example F-7 (PZT (110/52/48)) Comparative Sm 3% 2-ethylhexanoate Diethanolamine Oxygen 4.64 1400 Example F-8 Comparative Sm 3%2-ethyl butyrate Diethanolamine Oxygen 4.64 1400 Example F-9 ComparativeSm 3% Ethoxide Diethanolamine Oxygen 4.67 1410 Example F-10 ComparativeSm 3% n-butoxide Diethanolamine Oxygen 4.67 1410 Example F-11Comparative Sm 3% Acetylacetonate Diethanolamine Oxygen 4.67 1410Example F-12

TABLE 17 Addition element Specific species/Additive Added Sm AddedBaking Capacitance permittivity amount (mol %) compound form stabilizeratmosphere (μF/cm²) εr Example F-31 Sm 0.5% 2-ethyl hexanoateAcetylacetone Dry air 5.50 1660 Example F-32 Sm 0.5% 2-ethyl butyrateAcetylacetone Dry air 5.47 1650 Example F-33 Sm 0.5% EthoxideAcetylacetone Dry air 5.47 1650 Example F-34 Sm 0.5% n-butoxideAcetylacetone Dry air 5.47 1650 Example F-35 Sm 0.5% AcetylacetonateAcetylacetone Dry air 5.43 1640 Example F-36 Sm 1% 2-ethyl hexanoateAcetylacetone Dry air 5.76 1740 Example F-37 Sm 1% 2-ethyl butyrateAcetylacetone Dry air 5.76 1740 Example F-38 Sm 1% EthoxideAcetylacetone Dry air 5.73 1730 Example F-39 Sm 1% n-butoxideAcetylacetone Dry air 5.70 1720 Example F-40 Sm 1% AcetylacetonateAcetylacetone Dry air 5.73 1730 Example F-41 Sm 2% 2-ethyl hexanoateAcetylacetone Dry air 6.03 1820 Example F-42 Sm 2% 2-ethyl butyrateAcetylacetone Dry air 6.00 1810 Example F-43 Sm 2% EthoxideAcetylacetone Dry air 5.96 1800 Example F-44 Sm 2% n-butoxideAcetylacetone Dry air 6.00 1810 Example F-45 Sm 2% AcetylacetonateAcetylacetone Dry air 6.06 1830 Comparative Non dope — Acetylacetone Dryair 5.03 1520 Example F-13 (PZT (110/52/48)) Comparative Sm 3% 2-ethylhexanoate Acetylacetone Dry air 4.60 1390 Example F-14 Comparative Sm 3%2-ethyl butyrate Acetylacetone Dry air 4.67 1410 Example F-15Comparative Sm 3% Ethoxide Acetylacetone Dry air 4.64 1400 Example F-16Comparative Sm 3% n-butoxide Acetylacetone Dry air 4.67 1410 ExampleF-17 Comparative Sm 3% Acetylacetonate Acetylacetone Dry air 4.67 1410Example F-18

As can be seen from Tables 15 to 17, as compared to the PZTferroelectric thin films of Comparative Examples F-1, F-7 and F-13 withno addition of Sm, the ferroelectric thin films of Examples F-1 to F-45with an addition of Sm at a concentration of 0.5% to 2% exhibited a highcapacitance and a high specific permittivity at a thin film thickness ofabout 270 nm. From these results, it can be seen that the ferroelectricthin films of Examples F-1 to F-45 exhibit excellent basiccharacteristics as a capacitor.

However, the ferroelectric thin film of Comparative Examples F-2 to F6,F-8 to F-12, and F-14 to F-18, each with a 3% addition of Sm, exhibitedresults inferior to the PZT ferroelectric thin film of ComparativeExamples F-1, F-7 and F-13 with no addition of Sm.

In addition, according to the results of the ferroelectric thin films ofExamples F-1 to F-45 and Comparative Examples F-2 to F-6, F-8 to F-12and F-14 to F-18 with varying additive amounts of Sm, particularlyExamples F-11 to F-15, F-26 to F-30 and F-41 to F-45 with a 2% additionof Sm exhibited high numerical results in terms of capacitance andspecific permittivity, followed by in the order of: Examples F-6 toF-10, F-21 to F-25 and F-36 to F-40 with a 1% addition of Sm; ExamplesF-1 to F-5, F-16 to F-20 and F-31 to F-35 with a 0.5% addition of Sm;and Comparative Examples F-2 to F-6, F-8 to F-12 and F-14 to F-18 with a3% addition of Sm.

From these results, it was demonstrated that there is an appropriaterange of the Sm additive amount capable of contributing to improvementsof the capacitance and specific permittivity εr.

The ferroelectric thin film-forming composition of Examples F-1 to F-45,a method for forming a ferroelectric thin film and a ferroelectric thinfilm formed by the same method exhibit excellent basic characteristicsas a capacitor, and can be used for a thin film capacitor with a highcapacity density.

Hereinafter, Examples G-1 to G-45 of the present invention inconjunction with Comparative Examples G-1 to G-18 will be described inmore detail.

Examples G-1 to G-5

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various neodymium compounds (neodymium2-ethyl hexanoate, neodymium 2-ethyl butyrate, neodymium triethoxide,neodymium tri-n-butoxide, tris(acetylacetonate)neodymium) was added tothese sol-gel liquids, thereby obtaining five thin film-formingsolutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples G-6 to G-10

Ferroelectric thin films were formed on substrates in the same manner asin Examples G-1 to G-5, except that 1.0 mol % (in outer percent) ofvarious neodymium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples G-11 to G-15

Ferroelectric thin films were formed on substrates in the same manner asin Examples G-1 to G-5, except that 2.0 mol % (in outer percent) ofvarious neodymium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example G-1

A ferroelectric thin film was formed on a substrate in the same manneras in Examples G-1 to G-5, except that a thin film-forming solution wasprepared with no addition of neodymium compounds to the sol-gel liquid.

Comparative Examples G-2 to G-6

Ferroelectric thin films were formed on substrates in the same manner asin Examples G-1 to G-5, except that 3.0 mol % (in outer percent) ofvarious neodymium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples G-16 to G-20

First, zirconium tetra-n-butoxide and diethanolamine (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide anddiethanolamine (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various neodymium compounds (neodymium2-ethyl hexanoate, neodymium 2-ethyl butyrate, neodymium triethoxide,neodymium tri-n-butoxide, tris (acetylacetonate) neodymium) was added tothese sol-gel liquids, thereby obtaining five thin film-formingsolutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples G-21 to G-25

Ferroelectric thin films were formed on substrates in the same manner asin Examples G-16 to G-20, except that 1.0 mol % (in outer percent) ofvarious neodymium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples G-26 to G-30

Ferroelectric thin films were formed on substrates in the same manner asin Examples G-16 to G-20, except that 2.0 mol % (in outer percent) ofvarious neodymium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example G-7

A ferroelectric thin film was formed on a substrate in the same manneras in Examples G-16 to G-20, except that a thin film-forming solutionwas prepared with no addition of neodymium compounds to the sol-gelliquid.

Comparative Examples G-8 to G-12

Ferroelectric thin films were formed on substrates in the same manner asin Examples G-16 to G-20, except that 3.0 mol % (in outer percent) ofvarious neodymium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples G-31 to G-35

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various neodymium compounds (neodymium2-ethyl hexanoate, neodymium 2-ethyl butyrate, neodymium triethoxide,neodymium tri-n-butoxide, tris (acetylacetonate) neodymium) was added tothese sol-gel liquids, thereby obtaining five thin film-formingsolutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a dry air atmosphere at 700° C. for 1 minute, thereby forming aferroelectric thin film having a film thickness of 270 nm.

Examples G-36 to G-40

Ferroelectric thin films were formed on substrates in the same manner asin Examples G-31 to G-35, except that 1.0 mol % (in outer percent) ofvarious neodymium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples G-41 to G-45

Ferroelectric thin films were formed on substrates in the same manner asin Examples G-31 to G-35, except that 2.0 mol % (in outer percent) ofvarious neodymium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example G-13

A ferroelectric thin film was formed on a substrate in the same manneras in Examples G-31 to G-35, except that a thin film-forming solutionwas prepared with no addition of neodymium compounds to the sol-gelliquid.

Comparative Examples G-14 to G-18

Ferroelectric thin films were formed on substrates in the same manner asin Examples G-31 to G-35, except that 3.0 mol % (in outer percent) ofvarious neodymium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Evaluation

For a substrate on which each of the ferroelectric thin films preparedin Examples G-1 to G-45 and Comparative Examples G-1 to G-18 was formed,a Pt upper electrode of about 250 μm□ was fabricated on the surface ofthe substrate by a sputtering method using a metal mask, and C-Vcharacteristics (voltage dependence of capacitance) were evaluated at afrequency of 1 kHz and at a voltage of −5 to 5 V, between Pt lowerelectrodes immediately under the ferroelectric thin film. The specificpermittivity εr was calculated from the maximum value of capacitance.The measurement of C-V characteristics was carried out using a 4284Aprecision LCR meter (manufactured by HP) under the conditions of a biasstep of 0.1 V, a frequency of 1 kHz, an oscillation level of 30 mV, adelay time of 0.2 sec, a temperature of 23° C., and a hygrometry of50±10%. The results obtained are given in Tables 18 to 20 below.

TABLE 18 Addition element Specific species/Additive Added Nd AddedBaking Capacitance permittivity amount (mol %) compound form stabilizeratmosphere (μF/cm²) εr Example G-1 Nd 0.5% 2-ethyl hexanoateAcetylacetone Oxygen 5.48 1650 Example G-2 Nd 0.5% 2-ethyl butyrateAcetylacetone Oxygen 5.38 1620 Example G-3 Nd 0.5% EthoxideAcetylacetone Oxygen 5.45 1640 Example G-4 Nd 0.5% n-butoxideAcetylacetone Oxygen 5.41 1630 Example G-5 Nd 0.5% AcetylacetonateAcetylacetone Oxygen 5.45 1640 Example G-6 Nd 1% 2-ethyl hexanoateAcetylacetone Oxygen 6.35 1920 Example G-7 Nd 1% 2-ethyl butyrateAcetylacetone Oxygen 6.31 1900 Example G-8 Nd 1% Ethoxide AcetylacetoneOxygen 6.28 1890 Example G-9 Nd 1% n-butoxide Acetylacetone Oxygen 6.351920 Example G-10 Nd 1% Acetylacetonate Acetylacetone Oxygen 6.34 1910Example G-11 Nd 2% 2-ethyl hexanoate Acetylacetone Oxygen 5.41 1650Example G-12 Nd 2% 2-ethyl butyrate Acetylacetone Oxygen 5.51 1660Example G-13 Nd 2% Ethoxide Acetylacetone Oxygen 5.41 1630 Example G-14Nd 2% n-butoxide Acetylacetone Oxygen 5.35 1610 Example G-15 Nd 2%Acetylacetonate Acetylacetone Oxygen 5.45 1640 Comparative Non dope —Acetylacetone Oxygen 5.07 1530 Example G-1 (PZT (110/52/48)) ComparativeNd 3% 2-ethyl hexanoate Acetylacetone Oxygen 4.46 1360 Example G-2Comparative Nd 3% 2-ethyl butyrate Acetylacetone Oxygen 4.45 1340Example G-3 Comparative Nd 3% Ethoxide Acetylacetone Oxygen 4.55 1370Example G-4 Comparative Nd 3% n-butoxide Acetylacetone Oxygen 4.48 1350Example G-5 Comparative Nd 3% Acetylacetonate Acetylacetone Oxygen 4.461360 Example G-6

TABLE 19 Addition element Specific species/Additive Added Nd AddedBaking Capacitance permittivity amount (mol %) compound form stabilizeratmosphere (μF/cm²) εr Example G-16 Nd 0.5% 2-ethyl hexanoateDiethanolamine Oxygen 5.51 1660 Example G-17 Nd 0.5% 2-ethyl butyrateDiethanolamine Oxygen 5.48 1650 Example G-18 Nd 0.5% EthoxideDiethanolamine Oxygen 5.48 1650 Example G-19 Nd 0.5% n-butoxideDiethanolamine Oxygen 5.41 1630 Example G-20 Nd 0.5% AcetylacetonateDiethanolamine Oxygen 5.41 1630 Example G-21 Nd 1% 2-ethyl hexanoateDiethanolamine Oxygen 6.38 1920 Example G-22 Nd 1% 2-ethyl butyrateDiethanolamine Oxygen 6.31 1900 Example G-23 Nd 1% EthoxideDiethanolamine Oxygen 6.38 1920 Example G-24 Nd 1% n-butoxideDiethanolamine Oxygen 6.31 1900 Example G-25 Nd 1% AcetylacetonateDiethanolamine Oxygen 6.28 1890 Example G-26 Nd 2% 2-ethyl hexanoateDiethanolamine Oxygen 5.48 1650 Example G-27 Nd 2% 2-ethyl butyrateDiethanolamine Oxygen 5.45 1640 Example G-28 Nd 2% EthoxideDiethanolamine Oxygen 5.48 1650 Example G-29 Nd 2% n-butoxideDiethanolamine Oxygen 5.51 1660 Example G-30 Nd 2% AcetylacetonateDiethanolamine Oxygen 5.51 1660 Comparative Non dope — DiethanolamineOxygen 5.05 1520 Example G-7 (PZT (110/52/48)) Comparative Nd 3% 2-ethylhexanoate Diethanolamine Oxygen 4.58 1380 Example G-8 Comparative Nd 3%2-ethyl butyrate Diethanolamine Oxygen 4.58 1380 Example G-9 ComparativeNd 3% Ethoxide Diethanolamine Oxygen 4.52 1360 Example G-10 ComparativeNd 3% n-butoxide Diethanolamine Oxygen 4.52 1360 Example G-11Comparative Nd 3% Acetylacetonate Diethanolamine Oxygen 4.52 1360Example G-12

TABLE 20 Addition element Specific species/Additive Added Nd AddedBaking Capacitance permittivity amount (mol %) compound form stabilizeratmosphere (μF/cm²) εr Example G-31 Nd 0.5% 2-ethyl hexanoateAcetylacetone Dry air 5.45 1640 Example G-32 Nd 0.5% 2-ethyl butyrateAcetylacetone Dry air 5.51 1660 Example G-33 Nd 0.5% EthoxideAcetylacetone Dry air 5.41 1630 Example G-34 Nd 0.5% n-butoxideAcetylacetone Dry air 5.48 1650 Example G-35 Nd 0.5% AcetylacetonateAcetylacetone Dry air 5.48 1650 Example G-36 Nd 1% 2-ethyl hexanoateAcetylacetone Dry air 6.34 1910 Example G-37 Nd 1% 2-ethyl butyrateAcetylacetone Dry air 6.31 1900 Example G-38 Nd 1% EthoxideAcetylacetone Dry air 6.34 1910 Example G-39 Nd 1% n-butoxideAcetylacetone Dry air 6.28 1890 Example G-40 Nd 1% AcetylacetonateAcetylacetone Dry air 6.28 1890 Example G-41 Nd 2% 2-ethyl hexanoateAcetylacetone Dry air 5.48 1650 Example G-42 Nd 2% 2-ethyl butyrateAcetylacetone Dry air 5.45 1640 Example G-43 Nd 2% EthoxideAcetylacetone Dry air 5.48 1650 Example G-44 Nd 2% n-butoxideAcetylacetone Dry air 5.41 1630 Example G-45 Nd 2% AcetylacetonateAcetylacetone Dry air 5.41 1630 Comparative Non dope — Acetylacetone Dryair 5.05 1520 Example G-13 (PZT (110/52/48)) Comparative Nd 3% 2-ethylhexanoate Acetylacetone Dry air 4.48 1350 Example G-14 Comparative Nd 3%2-ethyl butyrate Acetylacetone Dry air 4.48 1350 Example G-15Comparative Nd 3% Ethoxide Acetylacetone Dry air 4.52 1360 Example G-16Comparative Nd 3% n-butoxide Acetylacetone Dry air 4.55 1370 ExampleG-17 Comparative Nd 3% Acetylacetonate Acetylacetone Dry air 4.55 1370Example G-18

As can be seen from Tables 18 to 20, as compared to the PZTferroelectric thin films of Comparative Examples G-1, G-7 and G-13 withno addition of Nd, the ferroelectric thin films of Examples G-1 to G-45with an addition of Nd at a concentration of 0.5% to 2% exhibited a highcapacitance and a high specific permittivity at a thin film thickness ofabout 270 nm. From these results, it can be seen that the ferroelectricthin films of Examples G-1 to G-45 exhibit excellent basiccharacteristics as a capacitor.

However, the ferroelectric thin film of Comparative Examples G-2 to G-6,G-8 to G-12, and G-14 to G-18, each with a 3% addition of Nd, exhibitedresults inferior to the PZT ferroelectric thin film of ComparativeExamples G-1, G-7 and G-13 with no addition of Nd.

In addition, according to the results of the ferroelectric thin films ofExamples G-1 to G-45, and Comparative Examples G-2 to G-6, G-8 to G-12and G-14 to G-18 with varying additive amounts of Nd, particularlyExamples G-6 to G-10, G-21 to G-25, and G-36 to G-40 with a 1% additionof Nd exhibited high numerical results in terms of capacitance andspecific permittivity, followed by in the order of: Examples G-1 to G-5,G-16 to G-20 and G-31 to G-35 with a 0.5% addition of Nd, and ExamplesG-11 to G-15, G-26 to G-30 and G-41 to G-45 with a 2% addition of Nd,which exhibit substantially the same results; and Comparative ExamplesG-2 to G-6, G-8 to G-12, and G-14 to G-18 with a 3% addition of Nd.

From these results, it was demonstrated that there is an appropriaterange of the Nd additive amount capable of contributing to improvementsof the capacitance and specific permittivity εr.

The ferroelectric thin film-forming composition of Examples G-1 to G-45,a method for forming a ferroelectric thin film and a ferroelectric thinfilm formed by the same method exhibit excellent basic characteristicsas a capacitor, and can be used for a thin film capacitor with a highcapacity density.

Hereinafter, Examples H-1 to H-45 of the present invention inconjunction with Comparative Examples H-1 to H-18 will be described inmore detail.

Examples H-1 to H-5

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various yttrium compounds (yttrium 2-ethylhexanoate, yttrium 2-ethyl butyrate, yttrium triethoxide, yttriumtri-n-butoxide, tris(acetylacetonate) yttrium) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples H-6 to H-10

Ferroelectric thin films were formed on substrates in the same manner asin Examples H-1 to H-5, except that 1.0 mol % (in outer percent) ofvarious yttrium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples H-11 to H-15

Ferroelectric thin films were formed on substrates in the same manner asin Examples H-1 to H-5, except that 2.0 mol % (in outer percent) ofvarious yttrium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example H-1

A ferroelectric thin film was formed on a substrate in the same manneras in Examples H-1 to H-5, except that a thin film-forming solution wasprepared with no addition of yttrium compounds to the sol-gel liquid.

Comparative Examples H-2 to H-6

Ferroelectric thin films were formed on substrates in the same manner asin Examples H-1 to H-5, except that 3.0 mol % (in outer percent) ofvarious yttrium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples H-16 to H-20

First, zirconium tetra-n-butoxide and diethanolamine (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide anddiethanolamine (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various yttrium compounds (yttrium 2-ethylhexanoate, yttrium 2-ethyl butyrate, yttrium triethoxide, yttriumtri-n-butoxide, tris(acetylacetonate) yttrium) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples H-21 to H-25

Ferroelectric thin films were formed on substrates in the same manner asin Examples H-16 to H-20, except that 1.0 mol % (in outer percent) ofvarious yttrium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples H-26 to H-30

Ferroelectric thin films were formed on substrates in the same manner asin Examples H-16 to H-20, except that 2.0 mol % (in outer percent) ofvarious yttrium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example H-7

A ferroelectric thin film was formed on a substrate in the same manneras in Examples H-16 to H-20, except that a thin film-forming solutionwas prepared with no addition of yttrium compounds to the sol-gelliquid.

Comparative Examples H-8 to H-12

Ferroelectric thin films were formed on substrates in the same manner asin Examples H-16 to H-20, except that 3.0 mol % (in outer percent) ofvarious yttrium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples H-31 to H-35

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.5mol % (in outer percent) of various yttrium compounds (yttrium 2-ethylhexanoate, yttrium 2-ethyl butyrate, yttrium triethoxide, yttriumtri-n-butoxide, tris(acetylacetonate) yttrium) was added to thesesol-gel liquids, thereby obtaining five thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof: Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a dry air atmosphere at 700° C. for 1 minute, thereby forming aferroelectric thin film having a film thickness of 270 nm.

Examples H-36 to H-40

Ferroelectric thin films were formed on substrates in the same manner asin Examples H-31 to H-35, except that 1.0 mol % (in outer percent) ofvarious yttrium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Examples H-41 to H-45

Ferroelectric thin films were formed on substrates in the same manner asin Examples H-31 to H-35, except that 2.0 mol % (in outer percent) ofvarious yttrium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example H-13

A ferroelectric thin film was formed on a substrate in the same manneras in Examples H-31 to H-35, except that a thin film-forming solutionwas prepared with no addition of yttrium compounds to the sol-gelliquid.

Comparative Examples H-14 to H-18

Ferroelectric thin films were formed on substrates in the same manner asin Examples H-31 to H-35, except that 3.0 mol % (in outer percent) ofvarious yttrium compounds was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Evaluation

For a substrate on which each of the ferroelectric thin films preparedin Examples H-1 to H-45 and Comparative Examples H-1 to H-18 was formed,a Pt upper electrode of about 250 μm□ was fabricated on the surface ofthe substrate by a sputtering method using a metal mask, and C-Vcharacteristics (voltage dependence of capacitance) were evaluated at afrequency of 1 kHz and at a voltage of −5 to 5 V, between Pt lowerelectrodes immediately under the ferroelectric thin film. The specificpermittivity εr was calculated from the maximum value of capacitance.The measurement of C-V characteristics was carried out using a 4284Aprecision LCR meter (manufactured by HP) under the conditions of a biasstep of 0.1 V, a frequency of 1 kHz, an oscillation level of 30 mV, adelay time of 0.2 sec, a temperature of 23° C., and a hygrometry of50±10%. The results obtained are given in Tables 21 to 23 below.

TABLE 21 Addition element Specific species/Additive Added Y (yttrium)Added Baking Capacitance permittivity amount (mol %) compound formstabilizer atmosphere (μF/cm²) εr Example H-1 Y (yttrium) 0.5% 2-ethylhexanoate Acetylacetone Oxygen 5.30 1600 Example H-2 Y (yttrium) 0.5%2-ethyl butyrate Acetylacetone Oxygen 5.37 1620 Example H-3 Y (yttrium)0.5% Ethoxide Acetylacetone Oxygen 5.47 1650 Example H-4 Y (yttrium)0.5% n-butoxide Acetylacetone Oxygen 5.37 1620 Example H-5 Y (yttrium)0.5% Acetylacetonate Acetylacetone Oxygen 5.37 1620 Example H-6 Y(yttrium) 1% 2-ethyl hexanoate Acetylacetone Oxygen 6.16 1860 ExampleH-7 Y (yttrium) 1% 2-ethyl butyrate Acetylacetone Oxygen 6.20 1870Example H-8 Y (yttrium) 1% Ethoxide Acetylacetone Oxygen 6.16 1860Example H-9 Y (yttrium) 1% n-butoxide Acetylacetone Oxygen 6.23 1880Example H-10 Y (yttrium) 1% Acetylacetonate Acetylacetone Oxygen 6.231880 Example H-11 Y (yttrium) 2% 2-ethyl hexanoate Acetylacetone Oxygen5.47 1650 Example H-12 Y (yttrium) 2% 2-ethyl butyrate AcetylacetoneOxygen 5.43 1640 Example H-13 Y (yttrium) 2% Ethoxide AcetylacetoneOxygen 5.43 1640 Example H-14 Y (yttrium) 2% n-butoxide AcetylacetoneOxygen 5.40 1630 Example H-15 Y (yttrium) 2% AcetylacetonateAcetylacetone Oxygen 5.47 1650 Comparative Non dope — AcetylacetoneOxygen 5.07 1530 Example H-1 (PZT (110/52/48)) Comparative Y (yttrium)3% 2-ethyl hexanoate Acetylacetone Oxygen 4.47 1350 Example H-2Comparative Y (yttrium) 3% 2-ethyl butyrate Acetylacetone Oxygen 4.441340 Example H-3 Comparative Y (yttrium) 3% Ethoxide AcetylacetoneOxygen 4.64 1400 Example H-4 Comparative Y (yttrium) 3% n-butoxideAcetylacetone Oxygen 4.51 1360 Example H-5 Comparative Y (yttrium) 3%Acetylacetonate Acetylacetone Oxygen 4.47 1350 Example H-6

TABLE 22 Addition element Specific species/Additive Added Y (yttrium)Added Baking Capacitance permittivity amount (mol %) compound formstabilizer atmosphere (μF/cm²) εr Example H-16 Y (yttrium) 0.5% 2-ethylhexanoate Diethanolamine Oxygen 5.33 1610 Example H-17 Y (yttrium) 0.5%2-ethyl butyrate Diethanolamine Oxygen 5.37 1620 Example H-18 Y(yttrium) 0.5% Ethoxide Diethanolamine Oxygen 5.37 1620 Example H-19 Y(yttrium) 0.5% n-butoxide Diethanolamine Oxygen 5.40 1630 Example H-20 Y(yttrium) 0.5% Acetylacetonate Diethanolamine Oxygen 5.37 1620 ExampleH-21 Y (yttrium) 1% 2-ethyl hexanoate Diethanolamine Oxygen 6.16 1860Example H-22 Y (yttrium) 1% 2-ethyl butyrate Diethanolamine Oxygen 6.231880 Example H-23 Y (yttrium) 1% Ethoxide Diethanolamine Oxygen 6.191870 Example H-24 Y (yttrium) 1% n-butoxide Diethanolamine Oxygen 6.191870 Example H-25 Y (yttrium) 1% Acetylacetonate Diethanolamine Oxygen6.16 1860 Example H-26 Y (yttrium) 2% 2-ethyl hexanoate DiethanolamineOxygen 5.43 1640 Example H-27 Y (yttrium) 2% 2-ethyl butyrateDiethanolamine Oxygen 5.47 1650 Example H-28 Y (yttrium) 2% EthoxideDiethanolamine Oxygen 5.47 1650 Example H-29 Y (yttrium) 2% n-butoxideDiethanolamine Oxygen 5.43 1640 Example H-30 Y (yttrium) 2%Acetylacetonate Diethanolamine Oxygen 5.43 1640 Comparative Non dope —Diethanolamine Oxygen 5.04 1520 Example H-7 (PZT (110/52/48))Comparative Y (yttrium) 3% 2-ethyl hexanoate Diethanolamine Oxygen 4.541370 Example H-8 Comparative Y (yttrium) 3% 2-ethyl butyrateDiethanolamine Oxygen 4.57 1380 Example H-9 Comparative Y (yttrium) 3%Ethoxide Diethanolamine Oxygen 4.60 1390 Example H-10 Comparative Y(yttrium) 3% n-butoxide Diethanolamine Oxygen 4.50 1360 Example H-11Comparative Y (yttrium) 3% Acetylacetonate Diethanolamine Oxygen 4.541370 Example H-12

TABLE 23 Addition element Specific species/Additive Added Y (yttrium)Added Baking Capacitance permittivity amount (mol %) compound formstabilizer atmosphere (μF/cm²) εr Example H-31 Y (yttrium) 0.5% 2-ethylhexanoate Acetylacetone Dry air 5.40 1630 Example H-32 Y (yttrium) 0.5%2-ethyl butyrate Acetylacetone Dry air 5.47 1650 Example H-33 Y(yttrium) 0.5% Ethoxide Acetylacetone Dry air 5.43 1640 Example H-34 Y(yttrium) 0.5% n-butoxide Acetylacetone Dry air 5.43 1640 Example H-35 Y(yttrium) 0.5% Acetylacetonate Acetylacetone Dry air 5.37 1620 ExampleH-36 Y (yttrium) 1% 2-ethyl hexanoate Acetylacetone Dry air 6.23 1880Example H-37 Y (yttrium) 1% 2-ethyl butyrate Acetylacetone Dry air 6.231880 Example H-38 Y (yttrium) 1% Ethoxide Acetylacetone Dry air 6.231880 Example H-39 Y (yttrium) 1% n-butoxide Acetylacetone Dry air 6.161860 Example H-40 Y (yttrium) 1% Acetylacetonate Acetylacetone Dry air6.16 1860 Example H-41 Y (yttrium) 2% 2-ethyl hexanoate AcetylacetoneDry air 5.43 1640 Example H-42 Y (yttrium) 2% 2-ethyl butyrateAcetylacetone Dry air 5.50 1660 Example H-43 Y (yttrium) 2% EthoxideAcetylacetone Dry air 5.50 1660 Example H-44 Y (yttrium) 2% n-butoxideAcetylacetone Dry air 5.43 1640 Example H-45 Y (yttrium) 2%Acetylacetonate Acetylacetone Dry air 5.43 1640 Comparative Non dope —Acetylacetone Dry air 5.03 1520 Example H-13 (PZT (110/52/48))Comparative Y (yttrium) 3% 2-ethyl hexanoate Acetylacetone Dry air 4.571380 Example H-14 Comparative Y (yttrium) 3% 2-ethyl butyrateacetylacetone Dry air 4.50 1360 Example H-15 Comparative Y (yttrium) 3%Ethoxide Acetylacetone Dry air 4.57 1380 Example H-16 Comparative Y(yttrium) 3% n-butoxide Acetylacetone Dry air 4.54 1370 Example H-17Comparative Y (yttrium) 3% acetylacetonate Acetylacetone Dry air 4.601390 Example H-18

As can be seen from Tables 21 to 23, as compared to the PZTferroelectric thin films of Comparative Examples H-1, H-7 and H-13 withno addition of Y (yttrium), the ferroelectric thin films of Examples H-1to H-45 with an addition of Y (yttrium) at a concentration of 0.5% to 2%exhibited a high capacitance and a high specific permittivity at a thinfilm thickness of about 270 nm. From these results, it can be seen thatthe ferroelectric thin films of Examples H-1 to H-45 exhibit excellentbasic characteristics as a capacitor.

However, the ferroelectric thin film of Comparative Examples H-2 to H6,H-8 to H-12, and H-14 to H-18, each with a 3% addition of Y (yttrium),exhibited results inferior to the PZT ferroelectric thin film ofComparative Examples H-1, H-7 and H-13 with no addition of Y (yttrium).

In addition, according to the results of the ferroelectric thin films ofExamples H-1 to H-45, and Comparative Examples H-2 to H-6, H-8 to H-12and H-14 to H-18 with varying additive amounts of Y (yttrium),particularly Examples H-6 to H-10, H-21 to H-25, and H-36 to H-40 with a1% addition of Y (yttrium) exhibited high numerical results in terms ofcapacitance and specific permittivity, followed by in the order of:Examples H-1 to H-5, H-16 to H-20 and H-31 to H-35 with a 0.5% additionof Y (yttrium), and Examples H-11 to H-15, H-26 to H-30 and H-41 to H-45with a 2% addition of Y (yttrium), which exhibit substantially the sameresults; and Comparative Examples H-2 to H-6, H-8 to H-12, and H-14 toH-18 with a 3% addition of Y (yttrium).

From these results, it was demonstrated that there is an appropriaterange of the Y (yttrium) additive amount capable of contributing toimprovements of the capacitance and specific permittivity εr.

The ferroelectric thin film-forming composition of Examples H-1 to H-45,a method for forming a ferroelectric thin film and a ferroelectric thinfilm formed by the same method exhibit excellent basic characteristicsas a capacitor, and can be used for a thin film capacitor with a highcapacity density.

[Group 3]

Hereinafter, Examples I-1 to I-75 of the present invention inconjunction with Comparative Examples I-1 to I-9 will be described inmore detail.

Examples I-1 to I-5

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.1mol % (in outer percent) of various carboxylic acids (2-ethyl hexanoicacid, 3-ethyl pentanoic acid, 2-ethyl butyric acid, iso-valeric acid,n-butyric acid) was added to these sol-gel liquids, thereby obtainingfive thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples I-6 to I-10

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-1 to I-5, except that 1.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Examples I-11 to I-15

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-1 to I-5, except that 3.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Examples I-16 to I-20

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-1 to I-5, except that 5.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Examples I-21 to I-25

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-1 to I-5, except that 10.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example I-1

A ferroelectric thin film was formed on a substrate in the same manneras in Examples I-1 to I-5, except that a thin film-forming solution wasprepared with no addition of various carboxylic acids to the sol-gelliquid.

Comparative Example I-2

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-1 to I-5, except that 5.0 mol % (in outer percent) ofpropionic acid was added to the sol-gel liquids to prepare thinfilm-forming solutions.

Comparative Example I-3

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-1 to I-5, except that 5.0 mol % (in outer percent) ofn-octanoic acid was added to the sol-gel liquids to prepare thinfilm-forming solutions.

Examples I-26 to I-30

First, zirconium tetra-n-butoxide and diethanolamine (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide anddiethanolamine (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.1mol % (in outer percent) of various carboxylic acids (2-ethyl hexanoicacid, 3-ethyl pentanoic acid, 2-ethyl butyric acid, iso-valeric acid,n-butyric acid) was added to these sol-gel liquids, thereby obtainingfive thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a 100% oxygen atmosphere at 700° C. for 1 minute, thereby forminga ferroelectric thin film having a film thickness of 270 nm.

Examples I-31 to I-35

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-26 to I-30, except that 1.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Examples I-36 to I-40

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-26 to I-30, except that 3.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Examples I-41 to I-45

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-26 to I-30, except that 5.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Examples I-46 to I-50

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-26 to I-30, except that 10.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example I-4

A ferroelectric thin film was formed on a substrate in the same manneras in Examples I-26 to I-30, except that a thin film-forming solutionwas prepared with no addition of various carboxylic acids to the sol-gelliquid.

Comparative Example I-5

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-26 to I-30, except that 5.0 mol % (in outer percent) ofpropionic acid was added to the sol-gel liquids to prepare thinfilm-forming solutions.

Comparative Example I-6

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-26 to I-30, except that 5.0 mol % (in outer percent) ofn-octanoic acid was added to the sol-gel liquids to prepare thinfilm-forming solutions.

Examples I-51 to I-55

First, zirconium tetra-n-butoxide and acetylacetone (stabilizer) wereadded to a reaction container, followed by reflux under a nitrogenatmosphere at a temperature of 150° C. Titanium tetraisopropoxide andacetylacetone (stabilizer) were added thereto, followed by reflux undera nitrogen atmosphere at a temperature of 150° C. Then, lead acetatetrihydrate and propylene glycol (solvent) were added thereto, followedby reflux under a nitrogen atmosphere at a temperature of 150° C. Then,by-products were removed by distillation under reduced pressure at 150°C., and propylene glycol was added thereto, followed by concentrationadjustment to obtain a liquid containing a 30% by mass concentration ofa metal compound in terms of oxides. Thereafter, dilute alcohol wasadded to obtain a sol-gel liquid containing a 10% by mass concentrationof a metal compound with a metal ratio of Pb/Zr/Ti=110/52/48 in terms ofoxides.

Next, the sol-gel liquid was divided into five equal portions, and 0.1mol % (in outer percent) of various carboxylic acids (2-ethyl hexanoicacid, 3-ethyl pentanoic acid, 2-ethyl butyric acid, iso-valeric acid,n-butyric acid) was added to these sol-gel liquids, thereby obtainingfive thin film-forming solutions.

Using these five thin film-forming solutions, thin films were formed bya CSD method, according to the following procedure. That is, eachsolution was applied by a spin coating method at 500 rpm for 3 secondsand then at 3000 rpm for 15 seconds to a 6 inch silicon substrate(Pt/TiO₂/SiO₂/Si(100) substrate) where a Pt thin film was sputtered onthe surface thereof. Subsequently, pre-baking was carried out by heatingthe substrate on a hot plate at 350° C. for 5 minutes. After theapplication and pre-baking processes were repeated 6 times, thesubstrate was subjected to baking in a rapid thermal annealer (RTA)under a dry air atmosphere at 700° C. for 1 minute, thereby forming aferroelectric thin film having a film thickness of 270 nm.

Examples I-56 to I-60

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-51 to I-55, except that 1.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Examples I-61 to I-65

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-51 to I-55, except that 3.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Examples I-66 to I-70

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-51 to I-55, except that 5.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Examples I-71 to I-75

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-51 to I-55, except that 10.0 mol % (in outer percent) ofvarious carboxylic acids was added to the sol-gel liquids to preparethin film-forming solutions.

Comparative Example I-7

A ferroelectric thin film was formed on a substrate in the same manneras in Examples I-51 to I-55, except that a thin film-forming solutionwas prepared with no addition of various carboxylic acids to the sol-gelliquid.

Comparative Example I-8

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-51 to I-55, except that 5.0 mol % (in outer percent) ofpropionic acid was added to the sol-gel liquids to prepare thinfilm-forming solutions.

Comparative Example I-9

Ferroelectric thin films were formed on substrates in the same manner asin Examples I-51 to I-55, except that 5.0 mol % (in outer percent) ofn-octanoic acid was added to the sol-gel liquids to prepare thinfilm-forming solutions.

Comparative Evaluation

For a substrate on which each of the ferroelectric thin films preparedin Examples I-1 to I-75 and Comparative Examples I-1 to H-9 was formed,a Pt upper electrode of about 250 μm□ was fabricated on the surface ofthe substrate by a sputtering method using a metal mask, and C-Vcharacteristics (voltage dependence of capacitance) were evaluated at afrequency of 1 kHz and at a voltage of −5 to 5 V, between Pt lowerelectrodes immediately under the ferroelectric thin film. The specificpermittivity εr was calculated from the maximum value of capacitance.The measurement of C-V characteristics was carried out using a 4284Aprecision LCR meter (manufactured by HP) under the conditions of a biasstep of 0.1 V, a frequency of 1 kHz, an oscillation level of 30 mV, adelay time of 0.2 sec, a temperature of 23° C., and a hygrometry of50±10%. The results obtained are given in Tables 24 to 26 below.

TABLE 24 Carboxylic acid Specific additive amount Added carboxylic AddedBaking Capacitance permittivity (mol %) acid form stabilizer atmosphere(μF/cm²) εr Example I-1 0.1%  2-ethyl hexanoic acid Acetylacetone Oxygen5.07 1540 Example I-2 0.1%  3-ethyl pentanoic acid Acetylacetone Oxygen5.04 1530 Example I-3 0.1%  2-ethylbutyric acid Acetylacetone Oxygen5.10 1550 Example I-4 0.1%  iso-valeric acid Acetylacetone Oxygen 5.041530 Example I-5 0.1%  n-butyric acid Acetylacetone Oxygen 5.04 1530Example I-6 1% 2-ethyl hexanoic acid Acetylacetone Oxygen 5.07 1540Example I-7 1% 3-ethyl pentanoic acid Acetylacetone Oxygen 5.07 1540Example I-8 1% 2-ethylbutyric acid Acetylacetone Oxygen 5.14 1560Example I-9 1% iso-valeric acid Acetylacetone Oxygen 5.07 1540 ExampleI-10 1% n-butyric acid Acetylacetone Oxygen 5.10 1550 Example I-11 3%2-ethyl hexanoic acid Acetylacetone Oxygen 5.17 1570 Example I-12 3%3-ethyl pentanoic acid Acetylacetone Oxygen 5.20 1580 Example I-13 3%2-ethylbutyric acid Acetylacetone Oxygen 5.27 1600 Example I-14 3%iso-valeric acid Acetylacetone Oxygen 5.20 1580 Example I-15 3%n-butyric acid Acetylacetone Oxygen 5.20 1580 Example I-16 5% 2-ethylhexanoic acid Acetylacetone Oxygen 5.93 1800 Example I-17 5% 3-ethylpentanoic acid Acetylacetone Oxygen 5.99 1820 Example I-18 5%2-ethylbutyric acid Acetylacetone Oxygen 5.93 1800 Example I-19 5%iso-valeric acid Acetylacetone Oxygen 5.96 1810 Example I-20 5%n-butyric acid Acetylacetone Oxygen 5.99 1820 Example I-21 10%  2-ethylhexanoic acid Acetylacetone Oxygen 5.76 1750 Example I-22 10%  3-ethylpentanoic acid Acetylacetone Oxygen 5.83 1770 Example I-23 10% 2-ethylbutyric acid Acetylacetone Oxygen 5.73 1740 Example I-24 10% iso-valeric acid Acetylacetone Oxygen 5.79 1760 Example I-25 10% n-butyric acid Acetylacetone Oxygen 5.79 1760 Comparative 0% —Acetylacetone Oxygen 4.97 1510 Example I-1 Comparative 5% Propionic acidAcetylacetone Oxygen 4.94 1500 Example I-2 Comparative 5% n-octanoicacid Acetylacetone Oxygen 4.97 1510 Example I-3

TABLE 25 Carboxylic acid Specific additive amount Added carboxylic AddedBaking Capacitance permittivity (mol %) acid form stabilizer atmosphere(μF/cm²) εr Example I-26 0.1%  2-ethyl hexanoic acid DiethanolamineOxygen 5.00 1520 Example I-27 0.1%  3-ethyl pentanoic acidDiethanolamine Oxygen 5.04 1530 Example I-28 0.1%  2-ethylbutyric acidDiethanolamine Oxygen 5.04 1530 Example I-29 0.1%  iso-valeric acidDiethanolamine Oxygen 5.07 1540 Example I-30 0.1%  n-butyric acidDiethanolamine Oxygen 5.00 1520 Example I-31 1% 2-ethyl hexanoic acidDiethanolamine Oxygen 5.13 1560 Example I-32 1% 3-ethyl pentanoic acidDiethanolamine Oxygen 5.10 1550 Example I-33 1% 2-ethylbutyric acidDiethanolamine Oxygen 5.10 1550 Example I-34 1% iso-valeric acidDiethanolamine Oxygen 5.13 1560 Example I-35 1% n-butyric acidDiethanolamine Oxygen 5.10 1550 Example I-36 3% 2-ethyl hexanoic acidDiethanolamine Oxygen 5.20 1580 Example I-37 3% 3-ethyl pentanoic acidDiethanolamine Oxygen 5.23 1590 Example I-38 3% 2-ethylbutyric acidDiethanolamine Oxygen 5.23 1590 Example I-39 3% iso-valeric acidDiethanolamine Oxygen 5.20 1580 Example I-40 3% n-butyric acidDiethanolamine Oxygen 5.23 1590 Example I-41 5% 2-ethyl hexanoic acidDiethanolamine Oxygen 5.99 1820 Example I-42 5% 3-ethyl pentanoic acidDiethanolamine Oxygen 5.96 1810 Example I-43 5% 2-ethylbutyric acidDiethanolamine Oxygen 5.96 1810 Example I-44 5% iso-valeric acidDiethanolamine Oxygen 5.96 1810 Example I-45 5% n-butyric acidDiethanolamine Oxygen 5.92 1800 Example I-46 10%  2-ethyl hexanoic acidDiethanolamine Oxygen 5.76 1750 Example I-47 10%  3-ethyl pentanoic acidDiethanolamine Oxygen 5.83 1770 Example I-48 10%  2-ethylbutyric acidDiethanolamine Oxygen 5.76 1750 Example I-49 10%  iso-valeric acidDiethanolamine Oxygen 5.79 1760 Example I-50 10%  n-butyric acidDiethanolamine Oxygen 5.79 1760 Comparative 0% — Diethanolamine Oxygen4.97 1510 Example I-4 Comparative 5% Propionic acid DiethanolamineOxygen 4.94 1500 Example I-5 Comparative 5% n-octanoic acidDiethanolamine Oxygen 4.94 1500 Example I-6

TABLE 26 Carboxylic acid Specific additive amount Added carboxylic AddedBaking Capacitance permittivity (mol %) acid form stabilizer atmosphere(μF/cm²) εr Example I-51 0.1%  2-ethyl hexanoic acid Acetylacetone Dryair 5.04 1530 Example I-52 0.1%  3-ethyl pentanoic acid AcetylacetoneDry air 5.04 1530 Example I-53 0.1%  2-ethylbutyric acid AcetylacetoneDry air 5.07 1540 Example I-54 0.1%  iso-valeric acid Acetylacetone Dryair 5.07 1540 Example I-55 0.1%  n-butyric acid Acetylacetone Dry air5.04 1530 Example I-56 1% 2-ethyl hexanoic acid Acetylacetone Dry air5.16 1570 Example I-57 1% 3-ethyl pentanoic acid Acetylacetone Dry air5.13 1560 Example I-58 1% 2-ethylbutyric acid Acetylacetone Dry air 5.131560 Example I-59 1% iso-valeric acid Acetylacetone Dry air 5.10 1550Example I-60 1% n-butyric acid Acetylacetone Dry air 5.10 1550 ExampleI-61 3% 2-ethyl hexanoic acid Acetylacetone Dry air 5.23 1590 ExampleI-62 3% 3-ethyl pentanoic acid Acetylacetone Dry air 5.26 1600 ExampleI-63 3% 2-ethylbutyric acid Acetylacetone Dry air 5.20 1580 Example I-643% iso-valeric acid Acetylacetone Dry air 5.26 1600 Example I-65 3%n-butyric acid Acetylacetone Dry air 5.26 1600 Example I-66 5% 2-ethylhexanoic acid Acetylacetone Dry air 5.98 1820 Example I-67 5% 3-ethylpentanoic acid Acetylacetone Dry air 5.95 1810 Example I-68 5%2-ethylbutyric acid Acetylacetone Dry air 5.98 1820 Example I-69 5%iso-valeric acid Acetylacetone Dry air 5.92 1800 Example I-70 5%n-butyric acid Acetylacetone Dry air 5.95 1810 Example I-71 10%  2-ethylhexanoic acid Acetylacetone Dry air 5.82 1770 Example I-72 10%  3-ethylpentanoic acid Acetylacetone Dry air 5.82 1770 Example I-73 10% 2-ethylbutyric acid Acetylacetone Dry air 5.75 1750 Example I-74 10% iso-valeric acid Acetylacetone Dry air 5.75 1750 Example I-75 10% n-butyric acid Acetylacetone Dry air 5.79 1760 Comparative 0% —Acetylacetone Dry air 5.00 1520 Example I-7 Comparative 5% Propionicacid Acetylacetone Dry air 4.97 1510 Example I-8 Comparative 5%n-octanoic acid Acetylacetone Dry air 4.97 1510 Example I-9

As can be seen from Tables 24 to 26, as compared to the PZTferroelectric thin films of Comparative Examples I-1, I-4 and I-7 withno addition of carboxylic acid and the PZT ferroelectric thin films ofComparative Examples I-2, I-3, I-5, I-6, I-8 and I-9 with an addition ofcarboxylic acid which does not take a 6-membered ring structure uponcoordination with a metal, the ferroelectric thin films of Examples I-1to I-75 with a 0.1% to 10% addition of carboxylic acid which can take a6-membered ring structure upon coordination with a metal exhibited ahigh capacitance and a high specific permittivity at a thin filmthickness of about 270 nm. From these results, it can be seen that theferroelectric thin films of Examples I-1 to I-75 exhibit excellent basiccharacteristics as a capacitor.

In addition, according to the results of the ferroelectric thin films ofExamples I-1 to G-75 with varying additive amounts of carboxylic acidwhich can take a 6-membered ring structure upon coordination with ametal, particularly Examples I-16 to I-20, I-41 to I-45 and I-66 to I-70with a 5% addition of carboxylic acid exhibited high numerical resultsin terms of capacitance and specific permittivity, followed by in theorder of: Examples I-21 to I-25, I-46 to I-50 and I-71 to I-75 with a10% addition of carboxylic acid; Examples I-11 to I-15, I-36 to I-40 andI-61 to I-65 with a 3% addition of carboxylic acid; Examples I-6 toI-10, I-31 to I-35 and I-56 to I-60 with a 1% addition of carboxylicacid; and Examples I-1 to I-5, I-26 to I-30 and I-51 to I-55 with a 0.1%addition of carboxylic acid.

From these results, when carboxylic acid is added which can take a6-membered ring structure upon coordination with a metal, it wasdemonstrated that there is an appropriate range of the additive amountcapable of contributing to improvements of the capacitance and specificpermittivity εr.

The ferroelectric thin film-forming composition of Examples I-1 to I-75,a method for forming a ferroelectric thin film and a ferroelectric thinfilm formed by the same method exhibit excellent basic characteristicsas a capacitor, and can be used for a thin film capacitor with a highcapacity density.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that additions, omissions, substitutions and othermodifications are possible, without departing from the scope and spiritof the invention. The present invention is not limited by theaforementioned description, and is confined only by the accompanyingclaims.

INDUSTRIAL APPLICABILITY

The ferroelectric thin film-forming composition, the method for forminga ferroelectric thin film and the ferroelectric thin film formed by thesame method, in accordance with the present invention, can be appliedfor use in composite electronic components of capacitors, IPDs, DRAMmemory condensers, multilayer capacitors, transistor gate insulators,nonvolatile memories, pyroelectric infrared detection devices,piezoelectric devices, electro-optical devices, actuators, resonators,ultrasonic motors, or LC noise filter devices.

1. A composition for the formation of a ferroelectric thin film which isused in the formation of a ferroelectric thin film of one materialselected from the group consisting of PLZT, PZT, and PT, wherein thecomposition is a liquid composition for the formation of a thin film ofa mixed composite metal oxide formed of a mixture of a composite metaloxide A represented by the general formula (1):(Pb_(x)La_(y))(Zr_(z)Ti_((1−z)))O₃ [In the formula (1), 0.9<x<1.3,0≦y<0.1, and 0≦z<0.9] with a composite oxide B including P (phosphorus),the composition comprising an organometallic compound solution whereinthe raw material constituting the composite metal oxide A and the rawmaterial constituting the composite oxide B are dissolved in an organicsolvent in such a proportion as to provide the metal atom ratiorepresented by the general formula (1).
 2. The composition for theformation of a ferroelectric thin film according to claim 1, wherein theraw material constituting the composite metal oxide A is a compoundwhose organic radical is bound to a metal element through oxygen ornitrogen atoms thereof.
 3. The composition for the formation of aferroelectric thin film according to claim 2, wherein the raw materialconstituting the composite metal oxide A is one or more selected fromthe group consisting of a metal alkoxide, a metal diol complex, a metaltriol complex, a metal carboxylate, a metal β-diketonato complex, ametal β-diketoester complex, a metal β-iminoketo complex, and a metalamino complex.
 4. The composition for the formation of a ferroelectricthin film according to claim 1, wherein the raw material constitutingthe composite oxide B includes P (phosphorus) and is a compound whoseorganic radical is bound to a P (phosphorus) element through oxygen ornitrogen atoms thereof.
 5. The composition for the formation of aferroelectric thin film according to claim 4, wherein the raw materialconstituting the composite oxide B includes P (phosphorus) and is one ormore selected from the group consisting of an alkoxide compound, a diolcompound, a triol compound, a carboxylate compound, a β-diketonatocompound, a β-diketoester compound, a β-iminoketo compound, and an aminocompound. 6-7. (canceled)
 8. The composition for the formation of aferroelectric thin film according to claim 1, further comprising one ormore stabilizers selected from the group consisting of β-diketone,β-ketonic acid, β-ketoester, oxy-acid, diol, triol, higher carboxylicacid, alkanol amine and polyamine, in a proportion of 0.2 to 3 mol per 1mol of the total amount of metals in the composition. 9-10. (canceled)11. The composition for the formation of a ferroelectric thin filmaccording to claim 1, wherein the composite oxide B includes P(phosphorus), and the molar ratio B/A of the composite oxide B to thecomposite metal oxide A is in the range of 0<B/A<0.2.
 12. Thecomposition for the formation of a ferroelectric thin film according toclaim 11, wherein the composite oxide B includes P (phosphorus), and themolar ratio B/A of the composite oxide B to the composite metal oxide Ais in the range of 0.003≦B/A≦0.1. 13-18. (canceled)
 19. A method forforming a ferroelectric thin film, comprising: applying a ferroelectricthin film-forming composition of claim 1 to a heat-resistant substrate;heating the substrate in air or under an oxidative atmosphere or watervapor-containing atmosphere, wherein the applying and the heating isperformed once or is repeated until the film reaches the desiredthickness; and baking the film at its crystallization temperature orhigher, at least during or after heating in the final step.
 20. Aferroelectric thin film formed by a method of claim
 19. 21. A compositeelectronic component of a thin-film condenser, a capacitor, an IPD, aDRAM memory condenser, a multilayer capacitor, a transistor gateinsulator, a nonvolatile memory, a pyroelectric infrared detectiondevice, a piezoelectric device, an electro-optical device, an actuator,a resonator, an ultrasonic motor, or an LC noise filter device which hasa ferroelectric thin film of claim
 20. 22. A composite electroniccomponent of a thin-film condenser, a capacitor, an IPD, a DRAM memorycondenser, a multilayer capacitor, a transistor gate insulator, anonvolatile memory, a pyroelectric infrared detection device, apiezoelectric device, an electro-optical device, an actuator, aresonator, an ultrasonic motor, or an LC noise filter device which has aferroelectric thin film of claim 21 and corresponding to a frequencyband of 100 MHz or higher. 23-41. (canceled)